Efficacy of cancer chemotherapy in relation to the pretreatment number of lymphocytes in patients with metastatic solid tumors

The evidence of lymphocytopenia has been demonstrated to predict a poor prognosis in terms of survival in advanced cancer patients. This finding is not surprising because of the fundamental role of lymphocytes in mediating tumor cell destruction. Despite the importance of lymphocytes in the pathogenesis of cancer, there are only few data about the profile and the function of lymphocytes during the various antitumor therapies, and in particular the relation between lymphocyte pretreatment number and response to chemotherapy remains to be established. The present study was performed to evaluate whether the evidence of lymphocytopenia before the onset of treatment may influence the efficacy of chemotherapy in metastatic cancer patients affected by the most frequent tumor types. The study included 183 patients (lung cancer: 89; colorectal cancer: 63; breast cancer: 31), 95 of whom had been previously treated with chemotherapy. The chemotherapeutic regimens consisted of oxaliplatin plus 5-fluorouracil and folates in untreated colorectal cancer, weekly irinotecan in pretreated colorectal cancer, cisplatin plus gemcitabine or etoposide in untreated lung cancer, weekly vinorelbine in pretreated lung cancer, and taxotere in breast cancer patients who had been previously treated with anthracyclines. Lymphocyte count was considered to be abnormally low for values below 1500/mm3. Lymphocytopenia was found in 79/183 (43%) patients, without any significant differences in relation to tumor histology. A complete response (CR) was achieved in 6/104 patients with a normal lymphocyte count and in none of the 79 lymphocytopenic patients. A partial response (PR) was obtained in 39 patients with a normal lymphocyte count and in only eight patients with a low lymphocyte count prior to therapy. Therefore, irrespective of the type of chemotherapy, the objective tumor response rate (CR + PR) in lymphocytopenic patients was significantly lower than in patients with normal pretreatment lymphocyte counts (8/79 vs 45/104; p < 0.001). This study shows that the evidence of lymphocytopenia prior to chemotherapy is associated with a lower efficacy of treatment in terms of objective tumor regression rates in patients with metastatic solid tumors, and suggests that the action of chemotherapy may depend at least in part on an interaction with the antitumor immunity. Pretreatment lymphocyte count may represent a new, simple biological marker to be taken into consideration by oncologists in the chemotherapeutic treatment of metastatic cancer.     

Combination of active specific immunotherapy or adoptive antibody or lymphocyte immunotherapy with chemotherapy in the treatment of cancer

Successful treatment of cancer patients with a combination of monoclonal antibodies (mAb) and chemotherapeutic drugs has spawned various other forms of additional combination therapies, including vaccines or adoptive lymphocyte transfer combined with chemotherapeutics. These therapies were effective against established tumors in animal models and showed promising results in initial clinical trials in cancer patients, awaiting testing in larger randomized controlled studies. Although combination between immunotherapy and chemotherapy has long been viewed as incompatible as chemotherapy, especially in high doses meant to increase anti-tumor efficacy, has induced immunosuppression, various mechanisms may explain the reported synergistic effects of the two types of therapies. Thus direct effects of chemotherapy on tumor or host environment, such as induction of tumor cell death, elimination of regulatory T cells, and/or enhancement of tumor cell sensitivity to lysis by CTL may account for enhancement of immunotherapy by chemotherapy. Furthermore, induction of lymphopenia by chemotherapy has increased the efficacy of adoptive lymphocyte transfer in cancer patients. On the other hand, immunotherapy may directly modulate the tumor’s sensitivity to chemotherapy. Thus, anti-tumor mAb can increase the sensitivity of tumor cells to chemotherapeutic drugs and patients treated first with immunotherapy followed by chemotherapy showed higher clinical response rates than patients that had received chemotherapy alone. In conclusion, combination of active specific immunotherapy or adoptive mAb or lymphocyte immunotherapy with chemotherapy has great potential for the treatment of cancer patients which needs to be confirmed in larger controlled and randomized Phase III trials.     

Changes in circulating dendritic cells and IL-12 in relation to the angiogenic factor VEGF during IL-2 immunotherapy of metastatic renal cell cancer

Angiogenesis and immunosuppression are the main biological mechanisms responsible for cancer progression. Moreover, recent observations suggesting a negative influence of angiogenesis on anticancer immunity have shown that some angiogenic factors, such as VEGF, may induce immunosuppression. In addition, the evidence of abnormally high blood levels of VEGF has been proven to be associated with resistance to IL-2 immunotherapy. The present study was performed to establish a possible relation ship between the efficacy of IL-2 cancer immunotherapy and changes in circulating levels of VEGF, IL-12, mature and immature dendritic cells (DC). The study included 25 metastatic renal cell cancer patients who underwent subcutaneous low-dose IL-2 immunotherapy (6 MIU/day for 6 days/week for 4 weeks). Immature and mature DCs were identified as CD123+ and CD11c+ cells, respectively. The clinical response consisted of partial response (PR) in five, stable disease (SD) in 11 and progressive disease (PD) in the remaining nine patients. The mean IL-12 levels observed during IL-2 immunotherapy were significantly higher in patients with PR or SD than in those with PD, whereas the mean VEGF concentrations were significantly higher in patients who had PD than in those with PR or SD. Finally, a significant increase in the mean number of circulating mature DCs occurred only in patients with PR or SD, whereas no significant change was seen in patients with PD. By contrast, no significant change was observed in the mean number of immature DCs. This study shows that the efficacy of IL-2 immunotherapy is associated with a significant increase in circulating mature DCs and IL-12, without any concomitant increase in VEGF concentrations. Further studies will be required to better define the relationship between activation of anticancer immunity and control of angiogenesis-related mechanisms.     

Changes in lymphocyte number during cancer chemotherapy and their relation to clinical response.

Since hematologic examination during cancer chemotherapy is generally limited to the evaluation of neutrophil and platelet numbers, at present there are no clear data about the possible prognostic significance of changes in lymphocyte number in relation to the clinical efficacy of chemotherapy itself. To obtain some preliminary data about this issue, we have evaluated changes in lymphocyte number and percentage in a group of 50 advanced non-small cell lung cancer patients treated with three cycles of cisplatin (20 mg/m2/day) plus etoposide (100 mg/m2/day) i.v. for three days every 21 days. The clinical response consisted of partial response (PR) in nine (18%), stable disease (SD) in 18 (36%) and progressive disease (PD) in the remaining 23 (46%) patients. The lymphocyte percentage increased during chemotherapy, without, however, a significant difference with respect to the pretreatment values. In contrast, the mean number of lymphocytes observed after the first chemotherapeutic cycle significantly decreased in patients with PD, whereas it increased in patients with PR or SD, even though the difference did not reach statistical significance. These preliminary data, which have to be confirmed in a large number of patients and in patients treated with other chemotherapeutic schedules for different tumor types, seem to suggest that a chemotherapy-induced decline in lymphocyte number may be associated with a lack of efficacy of chemotherapy itself.     

Chemoimmunotherapy: reengineering tumor immunity

Cancer chemotherapy drugs have long been considered immune suppressive. However, more recent data indicate that some cytotoxic drugs effectively treat cancer in part by facilitating an immune response to the tumor when given at the standard dose and schedule. These drugs induce a form of tumor cell death that is immunologically active, thereby inducing an adaptive immune response specific for the tumor. In addition, cancer chemotherapy drugs can promote tumor immunity through ancillary and largely unappreciated immunologic effects on both the malignant and normal host cells present within the tumor microenvironment. These more subtle immunomodulatory effects are dependent on the drug itself, its dose, and its schedule in relation to an immune-based intervention. The recent approvals of two new immune-based therapies for prostate cancer and melanoma herald a new era in cancer treatment and have led to heightened interest in immunotherapy as a valid approach to cancer treatment. A detailed understanding of the cellular and molecular basis of interactions between chemotherapy drugs and the immune system is essential for devising the optimal strategy for integrating new immune-based therapies into the standard of care for various cancers, resulting in the greatest long-term clinical benefit for cancer patients.     

Cytotoxic immunotherapy strategies for cancer: mechanisms and clinical development

Traditional therapies for cancer include surgery, chemotherapy, and radiation. Chemotherapy has widespread systemic cytotoxic effects against tumor cells but also affects normal cells. Radiation has more targeted local cytotoxicity but is limited to killing cells in the radiation field. Immunotherapy has the potential for systemic, specific killing of tumor cells. However, if the immune response is specific to a single antigen, tumor evasion can occur by down-regulation of that antigen. An immunotherapy approach that induces polyvalent immunity to autologous tumor antigens can provide a personalized vaccine with less potential for immunologic escape. A cytotoxic immunotherapy strategy creates such a tumor vaccine in situ. Immunogenic tumor cell death provides tumor antigen targets for the adaptive immune response and stimulates innate immunity. Attraction and activation of antigen presenting cells such as dendritic cells is important to process and present tumor antigens to T cells. These include cytotoxic T cells that kill tumor cells and T cells which positively and negatively regulate immunity. Tipping the balance in favor of anti-tumor immunity is an important aspect of an effective strategy. Clinically, immunotherapies may be most effective when combined with standard therapies in a complimentary way. An example is gene-mediated cytotoxic immunotherapy (GMCI) which uses an adenoviral vector, AdV-tk, to deliver a cytotoxic and immunostimulatory gene to tumor cells in vivo in combination with standard therapies creating an immunostimulatory milieu. This approach, studied extensively in animal models and early stage clinical trials, is now entering a definitive Phase 3 trial for prostate cancer.     

Combinatorial treatments including vaccines,chemotherapy and monoclonal antibodies for cancer therapy

Accumulating evidence suggests that despite the potency of cytotoxic anticancer agents, and the great specificity that can be achieved with immunotherapy, neither of these two types of treatment by itself has been sufficient to eradicate the disease. Still, the combination of these two different modalities holds enormous potential for eliciting therapeutic results. Indeed, certain chemotherapeutic agents have shown immunomodulatory activities, and several combined approaches have already been attempted. For instance, chemotherapy has been proven to enhance the efficacy of tumor cell vaccines, and to favor the activity of adoptively transferred tumor-specific T cells. A number of mechanisms have been proposed for the chemotherapy-triggered enhancement of immunotherapy response. Thus, chemotherapy may favor tumor cell death, and by that enhance tumor-antigen cross-presentation in vivo. Drug-induced myelosuppression may induce the production of cytokines favoring homeostatic proliferation, and/or ablate immunosuppression mechanisms. Furthermore, the recently reported synergy between monoclonal antibodies and chemotherapy or peptide vaccination is based upon the induction of endogenous humoral and cellular immune responses. This would suggest that monoclonal antibodies may not only provide passive immunotherapy but can also promote tumor-specific active immunity. This article will review several strategies in which immunotherapy can be exploited in preclinical and clinical studies in combination with other agents and therapeutic modalities that are quite unique when compared with “conventional” combination therapies (ie, treatments with chemotherapeutic drugs or chemotherapy and radiotherapy based protocols). The results from these studies may have significant implications for the development of new protocols based on combinatorial treatments including vaccines, chemotherapy and monoclonal antibodies, suggesting an exciting potential for therapeutic synergy with general applicability to various cancer types. Given the complicity of immune-based therapies and cancer pharmacology, it will be necessary to bring together cancer immunologists and clinicians, so as to provide a robust stimulus for realizing the successful management of cancer in the near future.     

Combinational adenovirus-mediated gene therapy and dendritic cell vaccine in combating well-established tumors

Recent developments in tumor immunology and biotechnology have made cancer gene therapy and immunotherapy feasible. The current efforts for cancer gene therapy mainly focus on using immunogenes, chemogenes and tumor suppressor genes. Central to all these therapies is the development of efficient vectors for gene therapy. By far, adenovirus （AdV）-mediated gene therapy is one of the most promising approaches, as has confirmed by studies relating to animal tumor models and clinical trials. Dendritic cells （DCs） are highly efficient, specialized antigen-presenting cells, and DC- based tumor vaccines are regarded as having much potential in cancer immunotherapy. Vaccination with DCs pulsed with tumor peptides, lysates, or RNA, or loaded with apoptotic/necrotic tumor cells, or engineered to express certain cytokines or chemokines could induce significant antitumor cytotoxic T lymphocyte （CTL） responses and antitumor immunity. Although both AdV-mediated gene therapy and DC vaccine can both stimulate antitumor immune responses, their therapeutic efficiency has been limited to generation of prophylactic antitumor immunity against re-challenge with the parental tumor cells or to growth inhibition of small tumors. However, this approach has been unsuccessful in combating well-established tumors in animal models. Therefore, a major strategic goal of current cancer immunotherapy has become the development of novel therapeutic strategies that can combat well-established tumors, thus resembling real clinical practice since a good proportion of cancer patients generally present with significant disease. In this paper, we review the recent progress in AdV-mediated cancer gene therapy and DC-based cancer vaccines, and discuss combined immunotherapy including gene therapy and DC vaccines. We underscore the fact that combined therapy may have some advantages in combating well-established tumors vis-a-vis either modality administered as a monotherapy.     

恒定自然杀伤T细胞与肿瘤免疫治疗

恒定自然杀伤T细胞(iNKT)是T淋巴细胞的一个独特亚群,兼具自然杀伤(NK)细胞和T细胞特征,同时表达T细胞受体(TCR)和NK细胞表面标志。iNKT细胞被激活后,通过分泌细胞因子,活化其它免疫细胞参与先天性免疫和获得性免疫,在抗肿瘤免疫过程中发挥调节作用。在多种癌症患者体内,发现外周血中iNKT细胞的数量降低、功能减弱,进而导致临床治疗效果不佳。近年来,基础研究和早期临床试验结果表明,注射抗原递呈细胞或/和体外培养并活化的iNKT细胞,抗肿瘤免疫治疗效果显著。本文就iNKT细胞的分类及生物学特性,在肿瘤免疫治疗中的作用与其机制,以及其临床应用等进行综述。     

Secondary lymphoid tissue chemokine mediates T cell-dependent antitumor responses in vivo

Secondary lymphoid tissue chemokine (SLC, also referred to as Exodus 2 or 6Ckine) is a recently identified high endothelial-derived CC chemokine. The ability of SLC to chemoattract both Th1 lymphocytes and dendritic cells formed the rationale to evaluate this chemokine in cancer immunotherapy. Intratumoral injection of recombinant SLC evidenced potent antitumor responses and led to complete tumor eradication in 40% of treated mice. SLC-mediated antitumor responses were lymphocyte dependent as evidenced by the fact that this therapy did not alter tumor growth in SCID mice. Studies performed in CD4 and CD8 knockout mice also revealed a requirement for both CD4 and CD8 lymphocyte subsets for SLC-mediated tumor regression. In immunocompetent mice, intratumoral SLC injection led to a significant increase in CD4 and CD8 T lymphocytes and dendritic cells, infiltrating both the tumor and the draining lymph nodes. These cell infiltrates were accompanied by the enhanced elaboration of Th1 cytokines and chemokines monokine induced by IFN-gamma and IFN-gamma-inducible protein 10 but a concomitant decrease in immunosuppressive cytokines at the tumor site. In response to irradiated autologous tumor, splenic and lymph node-derived cells from SLC-treated tumor-bearing mice secreted significantly more IFN-gamma, GM-CSF, and IL-12 and reduced levels of IL-10 than did diluent-treated tumor-bearing mice. After stimulation with irradiated autologous tumor, lymph node-derived lymphocytes from SLC-treated tumor-bearing mice demonstrated enhanced cytolytic capacity, suggesting the generation of systemic immune responses. These findings provide a strong rationale for further evaluation of SLC in tumor immunity and its use in cancer immunotherapy.     

Changes in circulating VEGF levels in relation to clinical response during chemotherapy for metastatic cancer

Abnormally high blood levels of vascular endothelial growth factor (VEGF) appear to be associated with a poor prognosis in advanced cancer, probably as a consequence of its angiogenic and immunosuppressive effects. The prognostic significance of changes in VEGF secretion during cancer chemotherapy is still unknown. This study aimed to investigate the relation between VEGF variations and therapeutic results during chemotherapy in advanced malignancies. The study included 90 metastatic cancer patients, 59 with non-small cell lung cancer and 31 with colorectal carcinoma. Chemotherapy consisted of cisplatin plus etoposide for NSCLC and camptothecin for colorectal cancer. Abnormally high (> 2 SD with respect to values in healthy controls) pretreatment VEGF levels were found in 38/90 (42%) patients. The percentage of non-progressive disease in response to chemotherapy was significantly higher in patients with normal levels of VEGF prior to therapy than in those with elevated pretreatment values of VEGF (10/32 vs 4/27; p < 0.05). Moreover, the percentage of VEGF level normalization during chemotherapy was significantly higher in patients with objective tumor response or stable disease than in progressing patients (10/18 vs 0/20; p < 0.001). Finally, among patients with tumor response or disease stabilization, the one-year survival rate was significantly higher in patients with chemotherapy-induced normalization of VEGF than in those with persistently high VEGF blood levels (9/10 vs 3/8; p < 0.05). These results suggest that changes in VEGF levels during chemotherapy may represent a useful biomarker to predict the effect of chemotherapy in terms of tumor response and survival in patients with metastatic solid neoplasms.     

DC-CIK治疗大肠癌的研究进展

大肠癌是消化道常见的恶性肿瘤之一,发病率和死亡率均较高。过继免疫治疗是当今肿瘤治疗的热点,已逐步成为一些肿瘤的首选治疗方法。树突状细胞(DC)是目前已知功能最强大的抗原呈递细胞,具有呈递肿瘤抗原和抵制肿瘤细胞免疫逃逸及刺激T淋巴细胞产生免疫应答的作用。细胞因子诱导的杀伤细胞(CIK)由多种细胞因子诱导而成,具有T淋巴细胞及NK细胞抗肿瘤作用的特点。DC和CIK细胞有效结合可以同时促进DC细胞的增殖和免疫功能及加强CIK细胞的抗肿瘤作用。本文就近年来国内外应用DC-CIK治疗大肠癌的研究进展进行综述。     

Re-purposing cancer therapeutics for breast cancer immunotherapy

After decades of work to develop immune-based therapies for cancer, the first drugs designed specifically to engage the host anti-tumor immune response for therapeutic benefit were recently approved for clinical use. Sipuleucel-T, a vaccine for advanced prostate cancer, and ipilimumab, a monoclonal antibody that mitigates the negative impact of cytotoxic T lymphocyte antigen-4 signaling on tumor immunity, provide a modest clinical benefit in some patients. The arrival of these drugs in the clinic is a significant advance that we can capitalize on for even better clinical outcomes. The strategic and scientifically rational integration of vaccines and other direct immunomodulators with standard cancer therapeutics should lead to therapeutic synergy and high rates of tumor rejection. This review focuses on the use of cyclophosphamide, doxorubicin, and HER-2-specific monoclonal antibodies to dissect mechanisms of immune tolerance relevant to breast cancer patients and illustrates how appropriate preclinical models can powerfully inform clinical translation. The immune-modulating activity of targeted, pathway-specific, small molecule therapeutics is also discussed. Fully understanding how cancer drugs impact the immune system should lead to the ultimate personalized cancer medicine: effective combinatorial immunotherapy strategies that simultaneously target signaling pathways essential for tumor growth and progression, and systematically break multiple, distinct immune tolerance pathways to maximize tumor rejection and effect cure.     

Interferon-alpha in tumor immunity and immunotherapy

Interferon-alpha (IFN-alpha) is a pleiotropic cytokine belonging to type I IFN, currently used in cancer patients. Early studies in mouse tumor models have shown the importance of host immune mechanisms in the generation of a long-lasting antitumor response to type I IFN. Recent studies have underscored new immunomodulatory effects of IFN-alpha, including activities on T and dendritic cells, which may explain IFN-induced tumor immunity. Reports on new immune correlates in cancer patients responding to IFN-alpha represent additional evidence on the importance of the interactions of IFN-alpha with the immune system for the generation of durable antitumor response. This knowledge, together with results from studies on genetically modified tumor cells expressing IFN-alpha, suggest novel strategies for using these cytokines in cancer immunotherapy and in particular the use of IFN-alpha as an immune adjuvant for the development of cancer vaccines.     

Adoptive cell therapy of prostate cancer using female mice-derived T cells that react with prostate antigens

In this study, we report a novel treatment strategy that could potentially be used to improve efficacy of adoptive cell therapy for patients with prostate cancer. We show that female C57BL/6 mice are able to effectively reject two syngeneic prostate tumors (TRAMP-C2 and RM1) in a T cell-dependent manner. The protective antitumor immunity appears to primarily involve T cell responses reactive against general prostate tumor/tissue antigens, rather than simply to male-specific H-Y antigen. For the first time we show that adoptive transfer of lymphocytes from TRAMP-C2-primed or naïve female mice effectively control prostate tumor growth in male mice, when combined with host pre-conditioning (i.e., non-myeloablative lymphodepletion) and IL-2 administration. No pathological autoimmune response was observed in the treated tumor-bearing male mice. Our studies provide new insights regarding the immune-mediated recognition of male-specific tissue, such as the prostate, and may offer new immunotherapy treatment strategies for advanced prostate cancer.     

Targeting TNF-α to neoangiogenic vessels enhances lymphocyte infiltration in tumors and increases the therapeutic potential of immunotherapy

Abnormal tumor vasculature impairs T lymphocyte adhesion to endothelial cells and lymphocyte extravasation into neoplastic tissues, limiting the therapeutic potential of both active and adoptive immunotherapies. We have found that treatment of tumor-bearing mice with NGR-TNF, a Cys-Asn-Gly-Arg-Cys peptide-TNF fusion product capable of altering the endothelial barrier function and improving drug penetration in tumors, associated with the intratumor upregulation of leukocyte-endothelial cell adhesion molecules, the release of proinflammatory cytokines and chemokines, and the infiltration of tumor-specific effector CD8(+) T cells. As a result, NGR-TNF enhanced the therapeutic activity of adoptive and active immunotherapy, delaying tumor growth and prolonging survival. Furthermore, we have found that therapeutic effects of these combinations can be further increased by the addition of chemotherapy. Thus, these findings might be relevant for the design of novel immunotherapeutic approaches for cancer patients.     

Phase II study of interleukin-2 and 13-cis-retinoic acid as maintenance therapy in metastatic colorectal cancer

Purpose We have previously shown that low-dose interleukin-2 (IL-2) and 13-cis-retinoic acid (13-cis-RA) improved lymphocyte and natural killer (NK) cell count of patients with advanced tumors showing a clinical benefit from chemotherapy. The primary endpoint of this study was to ask whether IL-2 and 13-cis-RA improved (≥30%) lymphocyte and NK cell count in patients with metastatic colorectal cancer (MCRC) that had a clinical benefit from induction chemotherapy. Secondary endpoint was the evaluation of toxicity, progression-free survival (PFS), and overall survival (OS). Patients and methods Forty patients with MCRC, showing a clinical benefit from chemotherapy, were treated with subcutaneous low-dose IL-2 (1.8 × 10⁶ IU) and oral 13-cis-RA (0.5 mg/kg) in order to maintain responses and improve survival through the increase of lymphocyte and NK cells. The biological parameters and the clinical outcome of these patients were compared with those of a control group of patients (80) with a similar disease status, including clinical benefit from chemotherapy. Results The most common adverse events were mild cutaneous skin rash and fever. After 4 months and 2 years of biotherapy, a statistically significant improvement was observed in lymphocyte and number of NK cells with respect to baseline values and to controls. After a median follow-up of 36 months, median PFS was 27.8 months, while median OS was 52.9 months. Conclusion These data show that maintenance immunotherapy with low-dose IL-2 and oral 13-cis-RA in patients with MCRC showing a clinical benefit from chemotherapy is feasible, has a low toxicity profile, improves lymphocyte and NK cell count. An improvement in the expected PFS and OS was also observed. A randomized trial is warranted.     

Immunologic approaches to the treatment of human cancer based on a guinea pig model

Summary Local immunotherapy is a form of cancer treatment where exogenous antigen is introduced into the area of the tumor. Under favorable circumstances, the perfused tumor regresses, systemic tumor-specific transplantation immunity is augmented, and distant microscopic metastases regress. Successful local immunotherapy requires an immunologically competent host, small tumor burden, and tumor located usually in the skin. A wide variety of biologic agents are capable of promoting local immunotherapy. BCG has been most widely studied. The antitumor activity of two different preparations of the Tice substrain of BCG were compared. No significant differences in antitumor activity were found. Alternative approaches to intralesional injection were sought. Intradermal injection of BCG adjacent to dermal tumors, prior to surgery, led to eradication of axillary metastases and to the development of tumor-specific transplantation immunity.Successful local BCG immunotherapy is a by-product of the host response to BCG infection. Involved are lymphocytes specifically sensitized to mycobacterial antigens, lymphocyte mediators, and macrophages which develop the capacity to kill tumor cells. Tumor-cell killing may be mediated by exocytosis of macrophage lysosomes into tumor cells. Complete and permanent tumor eradication probably requires the development of tumor-specific transplantation immunity mediated by sensitized lymphocytes. Local infection of the tumor may augment the development of this tumor-specific immunity.     

ZG16 regulates PD-L1 expression and promotes local immunity in colon cancer

CRC is a heterogeneous disease due to global molecular alterations, including mismatch-repair-deficient (dMMR) and microsatellite instability-high (MSI-H). Immunotherapy has achieved durable responses in a subset of patients with dMMR-MSI-H metastatic CRC. It has been showed that Loss of ZG16 is highly associated with colorectal cancer. However, whether ZG16 modulates tumor immunity in colorectal cancer is unclear. In this study, we demonstrated that the expression of ZG16 is associated with distant metastasis and lymphatic invasive in colorectal cancer. Besides, ZG16 is negatively correlated to PD-L1 expression in patient with CRC and overexpression of ZG16 blocks PD-L1 expression in colorectal cancer cells. In addition, overexpression of ZG16 promotes NK cells survival and proliferation, which is dependent on NKG2D expression. Our data demonstrate that ZG16 plays a role in modulation of immune response in colorectal cancer. The strong correlation between ZG16 and PD-L1 suggests that ZG16 may serve a biomarker to stratify patient who will benefit from immunotherapy.     

Biological response modifiers in cancer

We have seen a surge in the use of immunotherapy for the treatment of cancer. Biological response modifiers can act passively by enhancing the immunologic response to tumor cells or actively by altering the differentiation/growth of tumor cells. Active immunotherapy with cytokines such as interferons (IFNs) and interleukins (IL-2) is a form of nonspecific active immune stimulation. The use of IL-2 has recently been approved by the United States Food and Drug Administration (FDA) for the treatment of renal cell carcinoma and metastatic colorectal cancer. Considerable success has been achieved with the use of immunotherapy, especially in the area of passive immunotherapy using monoclonal antibodies--in particular, radiolabeled monoclonal antibodies. In addition to the various monoclonal antibodies that have been used in clinical trials, other strategies such as the use of antiangiogenic agents and matrix metalloprotease inhibitors (MMPIs) have also met with some success. Recently, the FDA approved bevacizumab, an anti-vascular endothelial growth factor (VEGF) agent, for the treatment of metastatic melanoma. This review also sheds light on the various angiogenesis inhibitors in clinical trials, the increasing use of thalidomide in cancer, and the upcoming potential cancer vaccines designed to activate cell-mediated immune responses against tumor antigens.