Expression of p185 and p53 in benign and malignant colorectal lesions

The c-erbB2 gene has been found to be amplified in a number of human adenocarcinomas, leading to elevated levels of expression of its encoded product, p185. Mutations in the p53 gene are also common in colorectal carcinomas, brain tumours, leukaemia and lymphomas.In this study, p185 and p53 overexpression was analyzed in colorectal adenomas (22 tubular adenomas and 2 tubulo-villous adenomas) and moderately differentiated adenocarcinomas (n = 22) in order to determine whether there was a relationship between these two proteins. The proteins are encoded by two genes located in the same chromosome. p185 and p53 expression was determined on tissue sections by immunohistochemical staining procedure.Expression of p185 was significantly higher (p < 0.01) in preneoplastic lesions (95.8% of cases) than colorectal cancer (63.6% of cases). p53 showed an inverse pattern to p185, being expressed in 58.3% of benign lesions and 72.7% of adenocarcinomas.These results confirm that p185 overexpression is associated with the early stages of colorectal cancer, whereas p53 is associated with more advanced stages. Although there was no correlation between p185 and p53 expression in premalignant lesions and adenocarcinomas, these two proteins have an important role in the adenoma–carcinoma sequence.     

The evaluation of human papillomavirus and p53 gene mutation in benign and malignant conjunctiva and eyelid lesions

Papillomas and squamous cell carcinomas are the most common conjunctival and eyelid lesions. The etiology is still unclear and recently human papillomavirus infection and p53 gene mutation have been taken into consideration. The aim of our study was the evaluation of HPV DNApresence and p53 gene mutation in 45 benign and 38 malignant squamous lesions of the conjunctiva and eyelid. For HPV detection PCR-RFLP and immunohistochemical reaction were used; for p53 gene mutation PCR-SSCP was used. Only 8.8% papillomas, 9.1% squamous cell cancers and 3.7% basal cell cancers (using PCR-RFLP method) and 26.6% papillomas, 7.4% squamous cell cancers and 9.1% basal cell cancers (using immunohisto-chemical reaction) were HPV positive. p53 gene mutation was evaluated in 24.4% papillomas, 54.5% squamous cell cancers and 22.2% basal cell cancers; most commonly in 6 and 7 exon. Human papillomavirus infection, opposite to p53 gene mutation, is not a significant etiological factor of the benign and malignant conjunctival and eyelid lesions development.     

Comparative studies of nuclear DNA content in benign and malignant thyroid lesions

Currently available data suggest that DNA aneuploidy is associated with aggressive behavior of and unfavorable prognosis in several malignant human tumors as compared with diploid malignancies. However, the diagnostic and prognostic importance of flow cytometric DNA measurements in the case of thyroid neoplasms remains controversial. Therefore, the aim of our study was to evaluate utility of DNA index (DI) and proliferative index (PI) in distinguishing benign from malignant thyroid lesions taking into account the possible influence of intra-tumor heterogeneity and tissue preparation mode on DNA flow-cytometry measurements. A retrospective study was performed on 71 paraffin-embedded specimens from 57 patients with benign and malignant thyroid pathologies: 13 colloid goitres, 12 parenchymatous goitres, 19 adenomas and 13 carcinomas. In 14 of 57 cases two separate specimens taken from different areas of the same lesion were analysed and DNA parameters were compared. Additionally, flow cytometry DNA analysis was parallelly performed on 3 adjacent but differently processed tissue sections (fresh, formalin-fixed and paraffin-embedded) taken from each of 26 surgically excised thyroid lesions. DNA content was also analysed in both fresh and formalin-fixed twin specimens of normal pig thyroid glands (N = 6). We demonstrated that all tumors diagnosed as thyroid carcinomas were associated with abnormal nuclear DNA content although aneuploidy was not found specific to malignant thyroid tumors. Aneuploid samples of benign thyroid lesions exhibited higher proliferative activity, expressed as mean PI values, than diploid ones. In carcinomas the mean PI values were significantly higher than in benign lesions, independently whether they concerned aneuploid or diploid tissues. Considering intra-tumor heterogeneity, the flow cytometric DNA parameters can be assumed as reproducible despite differences in the mode of tissue fixation and preparation for analysis.     

Karyometric study of benign and malignant diseases of the thyroid gland.

The results of the karyometric measurements in different thyroid diseases (both benign proliferative processes and cancer) have shown that this method may be useful in differential diagnosis of these diseases. It was also found that there are evident differences between the shapes of histograms in various forms of cancer. The shape of the histogram depends not only on the histological structure of the tumour (follicular, papillary, undifferentiated cancer), but also on the type of the cells of which it consists (A,B or C cells).     

The number of nucleoli in benign and malignant thyroid lesions: a useful diagnostic sign in cytological preparations

The slides of fine needle aspiration cytology specimens from 99 cases of cold thyroid nodules with known histology were reviewed and the number of nucleoli per nucleus counted and correlated with the different histopathological groups. Significant differences were observed between benign and malignant thyroid lesions in the number of nucleoli in the cytological material. Lower values were present in nodular goitres and follicular adenomas compared to carcinomas. In benign lesions the majority of nuclei contained one nucleolus and nuclei with two, three or more nucleoli were less frequent than in follicular, papillary, medullary and anaplastic carcinomas. Only one case of follicular adenoma had cells containing three or more nucleoli compared to more than half the cases of follicular carcinoma.     

p53, MDM2, bcl-2 staining in follicular neoplasms of the thyroid gland

Sixty-two follicular adenomas of the thyroid were investigated by immunohistochemistry for the expression of p53, MDM2 and bcl-2 proteins. The wild type of 393 aminoacid nuclear p53 phosphoprotein is the product of a gene located on the short arm of chromosome 17. The p53 protein controls the growth of transformed cells in a culture and thus termed a suppressor gene product. Mouse double minute 2 (MDM2) gene product has been described to occur in malignant epithelial tissue, the protein product of this gene binds to and presumably inactivates the growth suppressive effect of wild type p53 protein. Bcl-2 is an oncogene whose product inhibits apoptosis in many cells types. Some scattered nuclei in two adenomas (3.2%) stained positively for p53. The adenomas with positive staining for p53 were subserially sectioned, but no signs of invasion were found, both patients are alive and well. In 12 adenomas (19%) there was positive reaction for MDM2 protein, whereas none of them where p53 positive. All cases were strongly positive for bcl-2 staining. We conclude that p53 protein expression is not confined to follicular adenomas, while MDM2 and bcl-2 genes products are.     

Signaling Crosstalk of FHIT,p53, and p38 in etoposide-induced apoptosis in MCF-7 cells

Fragile histidine trail (FHIT) is a tumor suppressor in response to DNA damage which has been deleted in various tumors. However, the signaling mechanisms and interactions of FHIT with regard to apoptotic proteins including p53 and p38 in the DNA damage-induced apoptosis are not well described. In the present study, we used etoposide-induced DNA damage in MCF-7 as a model to address these crosstalks. The time course study showed that the expression of FHIT, p53, and p38MAPK started after 1 hour following etoposide treatment. FHIT overexpression led to increase p53 expression, p38 activation, and augmented apoptosis following etoposide-induced DNA damage compared to wild-type cells. However, FHIT knockdown blocked p53 expression, delayed p38 activation, and completely inhibited etoposide-induced apoptosis. Inhibition of p38 activity prevented induction of p53, FHIT, and apoptosis in this model. Thus, activation of p38 upon etoposide treatment leads to increase in FHIT and p53 expression. In p53 knockdown MCF-7, the FHIT induction was hampered but p38 activation was induced in lower doses of etoposide. In p53 knockdown cells, inhibition of p38 induced FHIT expression and apoptosis. Our data demonstrated that the exposure of MCF-7 cells to etoposide increases apoptosis through a mechanism involving the activation of the p38-FHIT-p53 pathway. Moreover, our findings suggest signaling interaction for these pathways may represent a promising therapy for breast cancer.     

Cellular protein alterations in colorectal cancer: p28, p53 and p65 studies

The expression and intracellular distribution of the p28 protein (MW 28 kD), which is electrophoretically specific for tumour cells, the p53 protein (MW 53 kD), one of the most frequently mutated in cancer, and the oncofoetal p65 protein (MW 65 kD), were investigated in colorectal cancer and normal colonic mucosa. The correlation between the expression of these proteins and the stage of the cancer, was evaluated. Neoplastic and normal tissues were fractionated by differential centrifugation, and protein analysis was performed by means of the Western blot technique in the presence of polyclonal (anti-p28 and anti-p65) or monoclonal (anti-p53) antibodies. Among the colorectal cancer cases examined 69% (11/16), 53% (10/19) and 77% (17/22) were positive for p28, p53 and p65, respectively. Immunoblot analysis revealed that the tumour specific p28 protein expression was mainly evident in the nuclear fraction, while the p53 and p65 proteins accumulated in the cell nuclei and the cytoplasm, although to different extents. The p65 protein appeared to be specifically expressed in the early stages of colorectal cancer, while a high level of p53 protein was typical for more invasive colorectal cancer stages.     

p53 and the malignant progression of Barrett's esophagus

Barrett's esophagus (BE) is a metaplastic disorder in which specialized columnar epithelium replaces healthy squamous epithelium (intestinal metaplasia). Even though its pathophysiology and the steps of its neoplastic progression are not completely understood, BE can be considered as a complication of gastroesophageal reflux disease (GERD). Given that esophageal adenocarcinoma, which is continually increasing in the Western world, still has a poor prognosis and suffers from late diagnosis, and because BE is a precancerous lesion, there is a strong need for good molecular markers of malignant progression in Barrett's metaplasia (BM). The aim of this review is to examine the published data regarding the role that assessment of p53 may play in the management of BE, trying to understand if it may be a useful marker to early diagnose BE malignant transformation.     

Evaluation of p53 and soluble Fas ligand (sFasL) serum level concentration as indicators of apoptosis in serum of patients with benign and malignant primary follicular thyroid tumors

INTRODUCTION: Apoptosis (programmed cell death) is the best described mode of physiological cell death. During embryonal development and morphogenesis, apoptosis may be induced by two pathways. The first is external protein signal originating from other cell--also named as "death signal". Another one is specific cell reaction for external stress factors. Blood concentration of proteins regulating both pathways of apoptosis may be useful in early diagnosis and staging of thyroid tumors. The aim of study was evaluation of p53 and sFasL blood concentration in patients with benign follicular adenoma and follicular thyroid cancer. MATERIALS AND METHODS: The study population was composed of 28 patients: 14 with thyroid carcinoma and 14 patients with follicular neoplasm (NF). All patients underwent surgical treatment. P53 and sFasL levels were evaluated before surgery and related to the histopathological diagnosis obtained post-surgery. RESULTS: The analysis revealed high sFasL blood concentration in patients with follicular thyroid cancer in comparison with the group with follicular adenoma. There was no statistically significant difference between levels of p53 in both groups. CONCLUSIONS: Evaluation of sFasL serum level concentration may be useful in preoperative diagnosis of follicular thyroid tumors.     

MED12 alterations in both human benign and malignant uterine soft tissue tumors

The relationship between benign uterine leiomyomas and their malignant counterparts, i.e. leiomyosarcomas and smooth muscle tumors of uncertain malignant potential (STUMP), is still poorly understood. The idea that a leiomyosarcoma could derive from a leiomyoma is still controversial. Recently MED12 mutations have been reported in uterine leiomyomas. In this study we asked whether such mutations could also be involved in leiomyosarcomas and STUMP oncogenesis. For this purpose we examined 33 uterine mesenchymal tumors by sequencing the hot-spot mutation region of MED12. We determined that MED12 is altered in 66.6% of typical leiomyomas as previously reported but also in 11% of STUMP and 20% of leiomyosarcomas. The mutated allele is predominantly expressed in leiomyomas and STUMP. Interestingly all classical leiomyomas exhibit MED12 protein expression while 40% of atypical leiomyomas, 50% of STUMP and 80% of leiomyosarcomas (among them the two mutated ones) do not express MED12. All these tumors without protein expression exhibit complex genomic profiles. No mutations and no expression loss were identified in an additional series of 38 non-uterine leiomyosarcomas. MED12 mutations are not exclusive to leiomyomas but seem to be specific to uterine malignancies. A previous study has suggested that MED12 mutations in leiomyomas could lead to Wnt/β-catenin pathway activation however our immunohistochemistry results show that there is no association between MED12 status and β-catenin nuclear/cytoplasmic localization. Collectively, our results show that subgroups of benign and malignant tumors share a common genetics. We propose here that MED12 alterations could be implicated in the development of smooth muscle tumor and that its expression could be inhibited in malignant tumors.     

Levels of circulating cell-free serum DNA in benign and malignant breast lesions

PURPOSES OF THE STUDY: We analyzed circulating cell-free DNA in the serum of patients with benign and malignant breast disease and in healthy individuals to determine its diagnostic value. BASIC PROCEDURES: Serum samples were obtained from 50 healthy individuals, 33 patients with malignant breast disease and 32 patients with benign breast disease. Circulatory DNA was extracted from serum samples. Cell-free DNA was quantified by real-time quantitative PCR for the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene. Tissue samples from patients with malignant and benign breast lesions were histopathologically examined. MAIN FINDINGS: The mean levels of circulating cell-free DNA in serum samples were 41,149 genome equivalents (GE)/mL in patients with malignant disease, 30,826 GE/mL in patients with benign disease, and 13,267 GE/mL in healthy individuals. Healthy individuals had significantly lower levels of cell-free DNA than patients with malignant or benign breast disease (p=0.001, p=0.031). No significant difference was observed between malignant and benign disease. There was a correlation between cell-free DNA levels and tumor size but not with other tumor characteristics. PRINCIPAL CONCLUSION: Our results suggest that levels of circulating cell-free DNA in serum could have diagnostic value to discriminate between healthy individuals and patients with breast lesions but not between patients with malignant and benign breast lesions.     

The associations of p53 overexpression with p53 codon 72 genetic polymorphism in esophageal cancer

Variations in p53 codon 72 have been identified as significant predisposing factors for various cancers, but molecular mechanisms remain unclear. We investigated associations of p53 overexpression with codon 72 variants and other factors with esophageal cancer. Status of p53 overexpression was determined by immunohistochemical staining. Codon 72 polymorphisms and mutation of p53 was identified by PCR-RFLP and direct sequencing from exons 4 to 9, respectively. We evaluated 126 patients who underwent esophagectomy in the National Taiwan University Hospital, and found that the status of p53 overexpression was significantly influenced by presence of codon 72 polymorphisms. After adjustment for other possible confounders, the incidence of p53 overexpression was significantly decreased in patients with Pro/Pro genotype with an odds ratio (OR) of 0.21 (95% CI: 0.067-0.64) (p = 0.0065) compared with incidence in patients with Arg/Arg genotype. The incidence of p53 overexpression was additively increased with environmental exposure to cigarette smoke, alcohol, and areca quid. When compared with individuals exposed to only one of these environmental risk factors, patients who had exposure to two or three risk factors had ORs of 6.11 (95% CI: 1.80-20.75) and 6.22 (95% CI: 1.81-21.34) for p53 overexpression, respectively. Elderly patients (age >70 years) were also more likely to have p53 overexpression, with an OR of 5.63 (95% CI: 1.53-20.64) compared with overexpression among patients aged less than 55 years. Forty-one patients received further evaluation of p53 mutation. There was also a higher incidence of, but without reaching a statistical significance, p53 mutation in patients with p53 overexpression (OR[95% CI]: 2.18 [0.52-9.6]) and codon 72 Arg/Arg genotype (OR [95% CI] of 0.8 [0.13-4.2], comparing genotypes of Pro/Pro and Arg/Pro with Arg/Arg). Our data provide the first observations that the presence of p53 codon 72 variants can be a significant factor influencing p53 overexpression in esophageal cancer, with overexpression also influenced by combined or prolonged environmental exposures.