The S-phase fraction of the aneuploid cell subpopulation is the biologically relevant one in aneuploid breast cancers.

BACKGROUND: In the case of DNA-aneuploid tumors there are no clear guidelines as to which S-phase fraction is the more relevant one: that corresponding to either the diploid or the aneuploid population, or rather an average of both. MATERIALS AND METHODS: We studied 280 breast cancer specimens from previously untreated patients. Histologically, 231 were ductal infiltrating carcinomas, 30 lobular infiltrating carcinomas and 19 corresponded to other, less frequent varieties. Postsurgically, 164 cases (58.6%) were classified as T1, 87 (31.1%) as T2 and 7 as T3. The remaining 22 cases were multifocal, diffuse tumors. Flow cytometry was performed on fresh tumor tissue, and immunohistochemistry for hormone receptors, Ki67, c-erb-B2 and p53 on paraffin-embedded material. RESULTS: In diploid tumors, a high S-phase (above the 75th percentile) correlated significantly with Ki67 expression > or =20% (p<0.0001). In aneuploid tumors, however, this was only the case for the aneuploid fraction of tumor cells (p< 0.0001). A high S-phase of diploid tumors correlated directly and significantly with a high histologic grade (p=0.04), a high nuclear grade (p=0.01), tumor size (p=0.0008), and inversely with estrogen (p<0.0001) and progesterone (p<0.0001) receptor expression. In aneuploid tumors, the aneuploid tumor fraction showed a direct and significant correlation with a high histologic grade (p=0.005), a high nuclear grade (p=0.001), mutant p53 expression (p=0.0009), and inversely with estrogen (p<0.0001) and progesterone (p=0.0001) receptor expression. A high S-phase of the diploid cell fraction of aneuploid tumors, on the other hand, just showed an inverse correlation with high nuclear grade of the tumors (p=0.02), and none whatsoever with all other tested parameters.

The X-chromosome RBMX Gene is Expressed in Mammary Carcinoma.

BACKGROUND: A gene located on the q11.23 region of the male chromosome, RBMY, which plays a role in spermatogenesis, is down-regulated in testicular cancer. RBMY is a diverged X-Y shared gene. The corresponding X chromosome gene, RBMX, is located on Xq26. MATERIALS AND METHODS: We studied fresh tissues from 122 infiltrating breast cancers (99 ductal infiltrating, 19 lobular infiltrating and 4 tubular carcinomas) for the expression of RBMX by means of differential RT-PCR (reverse transcription-polymerase chain reaction), using beta-actin as an internal control and normalization standard. The obtained results were compared with all available clinical and molecular data of the studied tumors (estrogen and progesterone receptors (ER & PR), c-erb-B2, p53, Ki67, DNA-ploidy, Bcl-2, VEGF, CD105 (endoglin), histologic variety, histologic and nuclear grade and axillary node invasion). RESULTS: RBMX RT-PCR was successful in 120/122 instances. All 120 cases expressed RBMX. The only significant correlation found between RBMX expression and all the variables tested was an inverse one with CD105 (endoglin) mRNA-expression (r=-3063; p=0.0007). CONCLUSION: The X-chromosome RBMX gene is expressed in all breast cancers. The expression is inversely correlated with the expression of the angiogenesis-associated CD105 (endoglin) gene. The precise meaning of this association has still to be elucidated.

Elevated mammaglobin (h-MAM) expression in breast cancer is associated with clinical and biological features defining a less aggressive tumour phenotype.

BACKGROUND: Mammaglobin (h-MAM) is expressed mainly by breast epithelial cells, and this feature has been used to detect circulating breast cancer cells and occult metastases in sentinel axillary lymph nodes of breast cancer patients. However, the biological role of mammaglobin is completely unknown. METHODS: We studied 128 fresh-frozen breast cancer specimens by means of reverse transcriptase-polymerase chain reaction and quantified their h-MAM mRNA expression. This was then correlated with histological and nuclear grade, oestrogen and progesterone receptor expression, c-erb-B2 and mutant p53 expression, as well as with cellular proliferation measured by means of the Ki67 labelling index, DNA ploidy and S-phase, and finally with the presence or not of invaded axillary nodes in the mastectomy specimen. RESULTS: In the univariate analysis, high h-MAM expression (above the median for the whole group) correlated significantly (P < 0.05) with oestrogen and progesterone receptor expression, diploid DNA content, low Ki67 labelling index, low nuclear grade and almost significantly (P = 0.058) with the absence of axillary nodal invasion in the mastectomy specimen. In a final, multivariate model, only progesterone receptor expression, diploid DNA content and absence of nodal invasion were found to be independently associated with high h-MAM expression. CONCLUSION: All of the features associated with mammaglobin expression reflect, without exception, a less aggressive tumour phenotype. Further studies are needed to clarify whether this is attributable to h-MAM expression itself, or to another mechanism of which mammaglobin expression forms part.

Immunofluorometric study of Bcl-2 and Bax expression in clinical fresh tumor samples from breast cancer patients.

BACKGROUND: The balance between the expression of the antiapoptotic gene Bcl-2 and the proapoptotic gene Bax is considered a good indicator of the apoptotic activity of tumor cells. Bcl-2 and Bax expression seem also to individually play a prognostic role in breast cancer. Our aim was to study the expression of both genes in fresh breast cancer samples, and to correlate the obtained results with other available clinical and biological parameters of the tumors. MATERIALS AND METHODS: Fresh tumor specimens from 86 breast cancer patients were studied by means of immunofluorocytometry for the expression of the apoptosis-associated Bcl-2 and Bax genes. Additionally, DNA-ploidy was also measured. Paraffin blocks corresponding to the same tumors were used for immunohistochemistry, to study the expression of hormone receptors (ER and PR), p53, c-erb-B2 and the Ki67 labelling index. Fourteen patients had been treated with four cycles of induction chemotherapy (cyclo-phosphamide, adriamycin and 5-fluorouracil), and separate statistical analyses were carried out both for the whole group, and for the 62 patients not having received any treatment whatsoever, in order to exclude any potential influence of the chemotherapeutic treatment on the expression of the studied antigens. RESULTS: Bcl-2 expression correlated significantly with estrogen (p = 0.002) and progesterone (p = 0.012) receptor expression, as well as with c-erb-B2 (p = 0.045) expression in chemotherapy-naïve tumors, the correlation being completely lost if treated tumors were added to the study group. A high apoptotic index (Bcl2/Bax < 0.5) correlated significantly with progesterone receptor expression (p = 0.037) and c-erb-B2 expression (p = 0.018), and this correlation was maintained, whether previously treated tumors were included into the study or not (p = 0.038 and p = 0.027, respectively). Bax expression did not correlate with any other clinical or biological parameters of the tumors, including Bcl-2 expression. CONCLUSION: Bcl-2 and Bax-expression can be easily determined in clinical breast cancer specimens by means of immunofluorocytometry. Bcl-2-expression significantly correlates with hormone-receptor- and c-erb-B2-expression exclusively in previously untreated tumors. This, however, seems only to be the case when considering Bcl-2 expression in isolation, since a high apoptotic index, which considers the ratio of Bcl-2 versus Bax expression in the same tumor, seems not to be affected by the previous use of chemotherapy.