Progression of mammary adenocarcinomas as reflected by nuclear DNA content

In 18 breast cancer patients the DNA histograms observed in the primary tumor at the date of diagnosis were compared with those found in the corresponding local and distant metastases at autopsy up to more than 12 yr later. All patients, except one, exhibited the same type of DNA histogram in both the primary tumor and its metastases. In one patient the DNA histogram changed from an euploid type in the primary breast carcinoma to an aneuploid type in the metastases. The results are interpreted as indicating that mammary adenocarcinoma in general exhibit a high degree of stability of the nuclear DNA content during the history of the disease. It is suggested that in breast cancer progression of the tumor disease is more likely due to a net increase and/or dissemination of tumor cells exhibiting similar genetic properties and malignancy potential than to a progressive dedifferentiation and increase of malignancy of the tumor cells.     

Intratumoral variations in DNA ploidy and s-phase fraction in human breast cancer.

To study intratumoral DNA ploidy heterogeneity and S-phase fraction (SPF) variability, we prospectively collected five different samples from 48 breast carcinomas and each sample was analysed separately by flow cytometry. Aneuploidy rate was 89.6% after analysis of four or five samples. DNA ploidy heterogeneity, i.e., different samples classified as either DNA euploid or DNA aneuploid in the same tumor was seen in 17%, and DNA index heterogeneity, i.e., tumor populations with different DNA indices (DIs) seen in different samples was 44%. A statistical model defining SPF heterogeneity is proposed. SPF heterogeneity as defined by us was 71%, and as expected the SPF heterogeneity rate increased significantly with increasing number of analysed samples. Four or more samples are needed to detect the most deviant (highest) SPF values. An unrecognized intratumor heterogeneity of DNA ploidy and SPF may partly explain the conflicting results reported in the literature on the above prognostic indicators.     

Expression of prolactin receptors in normal canine mammary tissue, canine mammary adenomas and mammary adenocarcinomas

ABSTRACT: BACKGROUND: Mammary tumors represent the most common neoplastic disease in female dogs. Recently, the promoting role of prolactin (PRL) in the development of human breast carcinoma has been shown. Possible proliferative, anti-apoptotic, migratory and angiogenic effects of PRL on human mammary cancer cells in vitro and in vivo were suggested. The effects of PRL are mediated by its receptor, and alterations in receptor expression are likely to play a role in tumor development. Currently, not much data is available about prolactin receptor (PRLR) expression in canine mammary tumors. To set the basis for investigations on the role of PRL in mammary tumorigenesis in this species, prolactin receptor expression was evaluated by semi-quantitative real time PCR and immunohistochemistry on 10 formalin-fixed, paraffinembedded samples each of canine non-neoplastic mammary tissue, mammary adenomas and adenocarcinomas. RESULTS: The highest PRLR expression levels were found in normal mammary tissue, while adenomas, and to an even higher degree adenocarcinomas, showed a significant decrease in prolactin receptor expression. Compared to normal tissue, PRLR mRNA was reduced 2.4 fold (p =0.0261) in adenomas and 4.8 fold (p = 0.008) in adenocarcinomas. PRLR mRNA expression was significantly lower in malignant than in benign lesions (p = 0.0165). Immunohistochemistry demonstrated PRLR expression in all three tissue types with signals mostly limited to epithelial cells. CONCLUSIONS: Malignant transformation of mammary tissue was associated with a decline in prolactin receptor expression. Further studies are warranted to address the functional significance of this finding.     

Medium chain fatty acid synthesis in rodent mammary adenocarcinomas in vitro

The ability or inability of certain rodent mammary adenocarcinomas to synthesize medium chain fatty acids in vitro, correlates with the presence or absence of the specific mammary chain-terminating enzyme, thioesterase II.     

Phenylketonuria: distribution of DNA diagnostic patterns in German families

Summary The distribution of DNA haplotype constellations within the phenylalanine hydroxylase (PAH) gene was investigated in 44 German families affected with phenylketonuria (PKU). The haplotype frequencies differed significantly from those observed in a Danish population. Furthermore, ten haplotypes were identified in addition to the 12 previously described. In one of ten PKU alleles linked to haplotype 3, the G to A transition at the 5 splice donor site of intron 12 could not be confirmed with the use of synthetic DNA probes. According to these data, which are still limited, carrier testing and prenatal diagnosis should be possible in 70% of individuals at risk in the German population.     

Intranuclear dynamics of DNA polymerase alpha differs between the transplanted R3230AC mammary adenocarcinomas and the host mammary gland depending on lactation cycle

DNA polymerase alpha activity was markedly higher in all nuclear subfractions, including nuclear matrix, from transplanted R3230AC mammary adenocarcinomas than in the analogous fractions from mammary gland of same tumor-bearing pregnant or lactating rats. Changes in host lactational status had no significant effect on subnuclear distribution of tumor DNA polymerase alpha activity, with the majority (60-75%) localized in soluble nucleoplasm and a significant amount (13-20%) retained in the nuclear matrix. In the host mammary gland, nuclear matrix-bound DNA polymerase alpha was highest, accounting for 48% of total nuclear activity, during late pregnancy when mammary cells undergo rapid raplication. During lactation, when cells in mammary gland cease to divide, only 8% of enzyme activity was in the nuclear matrix, while the majority (60-80%) of DNA polymerase alpha activity was localized in nucleoplasm. In both R3230AC tumor and mammary gland regardless of host's lactational status, the majority (60-80%) of DNA polymerase beta activity was localized in the high salt-soluble chromatin. These present data thus suggest that, regardless of host lactational status, R3230AC tumor has many cycling cells, each with a large pool of DNA polymerase alpha molecules maintaining maximal and constant replicative activity, while normal mammary gland cells have a smaller pool of DNA polymerase alpha which become primarily matrix-bound only during active cell replication during late pregnancy. A constant localization of nuclear DNA polymerase beta in chromatin in both mammary gland and the tumor suggest it is not important in mammary cell proliferation.     

Progesterone receptor involvement in independent tumor growth in MPA-induced murine mammary adenocarcinomas

We have developed a model of hormonal carcinogenesis in BALB/c female mice, in which MPA induced ductal mammary adenocarcinomas, expressing high levels of estrogen and progesterone receptors (ER and PR). A series of tumor lines, retaining both PR and ER expression, were obtained from selected tumors, which are maintained by syngeneic passages. In this model progesterone behaves as the growth-stimulating hormone (progesterone-dependent or PD tumors), whereas estrogens induce tumor regression. Through selective treatments we were able to derive a series of progesterone-independent (PI) variants. These lines do not require progesterone treatment to grow in ovariectomized female BALB/c mice, but retain, however, the expression of ER and PR. The aim of this paper is to investigate a possible regulatory role of the progesterone receptor (PR) on PI tumor growth. ER and PR were detected by immunocytochemistry in all lines studied. They were also characterized using biochemical assays and Scatchard plots. No differences in Kd of PR or ER were detected in PI variants. AR or GR were not detected in tumor samples using biochemical assays. Estradiol (5 mg silastic pellet) induced complete tumor regression in all tumors tested. We also evaluated the effects of different antiprogestins on tumor growth. Onapristone (10 mg/kg/day) and mifepristone (4.5 mg/kg/day) were able to induce complete tumor regression. The antiandrogen flutamide (5 mg silastic pellet) had no effect on tumor growth in agreement with the lack of androgen receptors. We used an in vitro approach to corroborate that the antiprogestin-induced inhibition was not attributable to an intrinsic effect. Cultures of a selected PI line were treated with PR antisense oligodeoxynucleotides (ASPR) to inhibit in vitro cell proliferation. A significant decrease of 3H-thymidine uptake was observed in cells of a PI line growing in the presence of 2.5% charcoalized fetal calf serum and 0.8-20 microg/ml ASPR. It can be concluded that the PR pathway is an essential path in the growth stimulation of PI tumors.     

Cytophotometrical and biochemical characterization of nonpalpable, mammographically detected mammary adenocarcinomas

Fifty nonpalpable, mammographically detected, invasive breast carcinomas were analysed with respect to DNA distribution pattern, steroid receptor content, and histopathological criteria. No significant histomorphological differences were found as compared to palpable breast carcinomas. In contrast, DNA distributions of palpable and nonpalpable tumors differed. Ninety percent of these relatively small breast carcinomas were found to exhibit nuclear DNA amounts within the diploid and tetraploid regions of normal breast epithelium. In earlier findings in palpable breast carcinomas, 55% are of the diploid-tetraploid type. The mean cellular content of the estrogen receptor was 1.0 fmole/microgram DNA in this group of mammographically detected carcinomas, which is significantly higher than in routinely detected, ie, larger, breast carcinomas. It is suggested that, despite the histomorphological findings, nonpalpable, mammographically detected breast carcinomas are dominated by biologically highly differentiated, slowly proliferating carcinomas with a favourable prognosis.     

Intratumoral DNA electroporation induces anti-tumor immunity and tumor regression

In situ expression of a foreign antigen and an immune-modulating cytokine by intratumoral DNA electroporation was tested as a cancer therapy regimen. Transgene expression in the tumors was sustained for 2–3 weeks after intratumoral electroporation with mammalian expression plasmid containing firefly luciferase cDNA. Electroporation with cDNA encoding tetanus toxin fragment C (TetC) induced tetanus toxin-binding antibody, demonstrating immune recognition of the transgene product. Intratumoral electroporation with TetC and IL-12 cDNA after mice were treated with CD25 mAb to remove regulatory T cells induced IFN-γ producing T-cell response to tumor-associated antigen, heavy inflammatory infiltration, regression of established tumors and immune memory to protect mice from repeated tumor challenge. Intratumoral expression of immune-modulating molecules may be most suitable in the neoadjuvant setting to enhance the therapeutic efficacy and provide long-term protection.     

Intratumoral BCG and Corynebacterium parvum therapy of canine mammary tumours before radical mastectomy

Summary In two parallel studies, bitches with mammary tumour received single intralesional injections of BCG (1 mg: 10⁷ living bacteria) and Corybacterium parvum (10⁹ killed bacteria) (53 bitches) or C. parvum alone (129 bitches) at the same dosage. Control groups received injections, following the same protocol, of 1 ml BCG suspension medium diluted in saline in the first study (51 bitches) or no injections at all (120 bitches in the second study).A block dissection, including mammary tumours, adjacent mammary glands, and regional lymph nodes, was performed 2 weeks later in all animals. On the basis of histologically confirmed malignant tumours, 48 bitches (25 treated by immunotherapy and 23 controls) in the first study and 67 bitches (30 treated by immunotherapy and 37 controls) in the second study remained for postsurgical follow-up.The clinical tolerance of the treatment was generally good. No significant differences were found in cumulative survival rates between treated and control group in either studies.     

Thymic involution and thymocyte phenotypic alterations induced by murine mammary adenocarcinomas

A profound thymic atrophy has been observed in mice bearing large adenocarcinomas of the mammary gland. Only 2 to 5% of thymocytes remained 4 wk after tumor implantation. Although there is a slight decrease in the overall percentages of Thy-1+ cells in tumor bearers, the majority of the remaining cells are of a Thy-1 low phenotype. There was a lower percentage of double positive (CD4+, CD8+) cells, an increase of CD4+ CD8- thymocytes, similar percentages of CD4- CD8+ cells and double negative (CD4- CD8-) thymocytes in tumor-bearing mice. In addition, an increased percentage of CD3 cells could be detected in these animals. These results indicate that proportionally less immature thymocytes are present in the atrophic thymuses of mammary tumor bearers. Enhanced levels of glucocorticoids are known to produce similar effects on the thymus. However, adrenalectomy of mice followed by tumor implantation did not result in reversal of the thymic atrophy. Furthermore, a study of serum corticosterone levels in tumor bearers indicated no significant changes during tumorigenesis. A study of several parameters of bone marrow (BM) populations indicate that there is an increase in cells of the granulocyte-macrophage lineage and a decrease in lymphocytes induced by tumor-derived granulocyte macrophage-CSF. An alteration of prothymocytes in the BM is not the main cause of the thymic atrophy because BM cells from normal and tumor-bearing mice reconstituted irradiated normal mice equally well. There was no preferential recruitment of double positive cells to the spleen as indicated by no significant differences in the levels of T cells of immature phenotype including the CD4+ CD8+ population in the spleens of tumor bearers. Because no major changes were observed in tumor bearers, either at their capacity to repopulate the thymus or at the patterns of subsequent redistribution of thymocytes, it was postulated that the thymic atrophy may be caused by a direct or indirect effect of the tumor or tumor-associated factor(s). Intrathymic injections of tumor cells into young normal recipient mice resulted in a significant reduction of the thymus weight and cellularity. These data suggest that mammary tumors can secrete factor(s) that are capable of severely impairing the normal development of cells of the T cell lineage.     

Signatures of DNA flexibility, interactions and sequence-related structural variations in classical X-ray diffraction patterns

The theory of X-ray diffraction from ideal, rigid helices allowed Watson and Crick to unravel the DNA structure, thereby elucidating functions encoded in it. Yet, as we know now, the DNA double helix is neither ideal nor rigid. Its structure varies with the base pair sequence. Its flexibility leads to thermal fluctuations and allows molecules to adapt their structure to optimize their intermolecular interactions. In addition to the double helix symmetry revealed by Watson and Crick, classical X-ray diffraction patterns of DNA contain information about the flexibility, interactions and sequence-related variations encoded within the helical structure. To extract this information, we have developed a new diffraction theory that accounts for these effects. We show how double helix non-ideality and fluctuations broaden the diffraction peaks. Meridional intensity profiles of the peaks at the first three helical layer lines reveal information about structural adaptation and intermolecular interactions. The meridional width of the fifth layer line peaks is inversely proportional to the helical coherence length that characterizes sequence-related and thermal variations in the double helix structure. Analysis of measured fiber diffraction patterns based on this theory yields important parameters that control DNA structure, packing and function.     

Compositional variations in DNA sequences

Biologically occurring nucleotide sequences differ from randomlygenerated ones. Here we describe general patterns found in prokaryoticand in eukaryotic DNA. In the accompanying paper (Nussinov,1991) we also describe DNA signals recognized by their correspondingprotein factors. In particular, we focus on modes of searchesfor such patterns and signals and on the potential propertiessuch sequences may possess.     

Nuclear DNA ploidy in mammary carcinomas; using nuclear size as co-parameter reveals more complex patterns.

Static DNA measurements using nuclear size as a co-parameter have been made on cell populations from 106 consecutive patients with proper imprints from fresh tumour tissues or fine-needle aspirates. When DNA content is plotted against the nuclear size of each individual cancer cell in a scatter diagram, different patterns are found. These patterns indicate the presence of subpopulations, which may be overlooked using conventional flow cytometric analysis or other techniques relying only on the nuclear DNA content. The presence of these subpopulations might, in addition, interfere with a correct definition and estimation of the percentage of S-phase cells.     

Aberrant E-cadherin staining patterns in invasive mammary carcinoma

Background

Advances in our understanding of the molecular biology of colorectal cancer have fuelled the search for novel molecular prognostic markers to complement existing staging systems. Markers assessed in combination may perform better than those considered individually. Using high-throughput tissue microarray technology, we describe the prognostic value of combined p53 / Bcl-2 status in colorectal cancer.

Patients and methods

Tumour samples from 462 patients who underwent elective surgery to resect a primary colorectal cancer between 1994 and 2000 (mean follow-up of 75 months) were assembled in tissue microarray format. Clinico-pathological data including tumour grade, stage, vascular invasion status along with disease specific survival data has been collected prospectively. Immunohistochemical analysis of p53 and Bcl-2 expression was performed using antibodies DO-7 (p53) and 124 (Bcl-2), and results correlated with known clinico-pathological variables and outcomes.

Results

Abnormal nuclear p53 accumulation and Bcl-2 overexpression were detected in 221/445 (49.6%) and199/437 (45.5%) tumours respectively, with a significant inverse correlation between the two markers (p = 0.023). On univariate analysis no correlations were found between either marker and standard clinico-pathological variables, however nuclear p53 expression was associated with a significantly reduced survival (p = 0.024). Combined analysis of the two markers indicated that 112/432 (24.2%) cases displayed a p53(-)/Bcl-2(+) phenotype, this occurring more frequently in earlier stage tumours. Kaplan-Meier analysis revealed a significant survival advantage in these p53(-)/Bcl-2(+) tumours compared with the remaining cases (p = 0.0032). On multivariate analysis using the Cox proportional hazards model, neither p53 expression nor Bcl-2 expression alone were of independent prognostic significance, however the combined p53(-)/Bcl-2(+) phenotype was significantly associated with a good prognosis in this series (HR 0.659, 95%CI 0.452–0.959, p = 0.029).

Conclusion

Patient stratification by combined p53 / Bcl-2 phenotype provides stage-independent prognostic information in colorectal cancer. Specifically, that up to a quarter of patients display a good prognosis p53(-)/Bcl-2(+) phenotype. This may indicate a more clinically indolent phenotype and a subset of patients for whom less aggressive adjuvant treatment appropriate.