Bcl-2 expression in breast cancer: a comparative study at the mRNA and protein level.

BACKGROUND: Bcl-2 is one of the most important antiapoptotic genes. Although it facilitates the survival of tumor cells, its expression has been consistently associated with a better prognosis for breast cancer. Virtually all studies on Bcl-2 conducted in breast cancer have been carried out by means of immunohistochemistry. The aim of this study was to examine for the first time the expression of Bcl-2 in a series of human breast cancer, both at the mRNA and protein level. MATERIALS AND METHODS: One hundred samples from previously untreated human breast cancers were used; Bcl-2 expression was determined both by means of immunohistochemistry using the bcl-2/100/D5 monoclonal antibody and differential RT-PCR. Additionally, the expression of hormone receptors (ER and PR), c-erb-B2, p53 and the proliferation-associated Ki-67 antigen were also studied by means of immunohistochemistry as part of the standard pathological workup. RESULTS: Any degree of immunohistochemical staining correlated significantly and inversely with c-erb-B2 expression (p = 0.0008), nuclear grade 3 (p = 0.0015), a Ki-67 labeling index > 10% (p = 0.02) and tumor size (p = 0.048), and in a direct fashion with estrogen (p = 0.0003) and progesterone receptor expression (p = 0.0002). mRNA expression of the Bcl-2 gene showed a significant inverse correlation with c-erb-B2 (p = 0.016) and p53 (p = 0.014) expression, as well as with a nuclear grade 3 (p = 0.006), and a direct correlation with estrogen (p = 0.0004) and progesterone (p = 0.001) receptor expression, as well as with nodal invasion (p = 0.04). CONCLUSION: The study of Bcl-2 expression in breast cancer by means of either immunohistochemistry or RT-PCR yields very similar results. In spite of its role opposing tumor cell death, Bcl-2 is associated with biological features of the tumors which define a better intrinsic prognosis, such as hormone receptor expression, low proliferation and absence of c-erb-B2 and mutant p53 expression. This may in great part explain why Bcl-2 expression has been invariably found to correlate with a better prognosis of breast cancer.

Molecular subgroups of small (pT1) breast carcinomas belonging exclusively to the ductal infiltrating variety.

BACKGROUND: The use of microarray technology has resulted in a new classification of breast cancer according to gene expression profiles. None of the reports published so far using this new classification has stratified the studied tumors by histology or size. MATERIALS AND METHODS: This study was restricted to the ductal infiltrating variety only, and to pT1 size using the immunohistochemical markers estrogen receptor (ER), progesterone receptor (PR), HER2 and cytokeratin 5/6. ER+ and/or PR+, HER2- tumors were termed "luminal A"; ER+ and/or PR+, HER2+ "luminal B"; triple-negative, CK 5/6+ and/or HER1+ "basal-like"; with an additional category for ER-, PR-, HER2+ tumors termed HER2, and a final group of unclassified ones, negative for all five markers. RESULTS: Out of 346 tumors, 251 (72.5%) were luminal A, 45 (13%) were "triple-negative" ("basal"-like), 20 (5.8%) were luminal B, and 30 (8.7%) were HER2. Luminal A, "triple-negative" ("basal"-like), and HER2-expressing tumors (luminal B + HER2) showed significantly different associations with histological and nuclear grade, mutant p53 expression and Ki67 labelling index. CONCLUSION: Studies of the other, less frequent histological varieties of breast cancer, stratifying by tumor size, are mandatory to disclose which precise gene-expression pattern defines similar subgroups.

Proliferation measurement in breast cancer by two different methods.

BACKGROUND: Different studies show that proliferation measurement in breast cancer may have an independent prognostic value. In the present study, tumor proliferation in breast cancer was analyzed by two radically different methods according to the technique used (immunohistochemistry and flow cytometry), associated costs and necessary equipment. The aim was to evaluate which method discriminates better between tumors with high and low proliferation in relation to all other available clinical and biological parameters. MATERIALS AND METHODS: Two hundred and eighty breast cancers (231 ductal infiltrating, 30 lobular, 19 or less frequent varieties) were studied. The post-surgical staging was as follows: 164 pT1, 87 pT2, 7 pT3, the remaining 22 were multifocal, diffuse tumors. Axillary nodal invasion was found in 99 cases (35.4%). Proliferation was studied by means of flow cytometry (DNA index and S-phase) in fresh tumor tissue and immunohistochemistry (Ki67) in paraffin-embedded tissue. Furthermore, hormone receptor (estrogen receptor, ER; progesterone receptor, PR), c-erb-B2 and p53 expressions were studied using the same method. Finally, histological and nuclear grade, tumor size and axillary nodal invasion were also included as variables of the study. RESULTS: A DNA index >1 (aneuploidy) correlated significantly with histological grade 3 (p = 0.01), nuclear grade 3 (p < 0.0001), nodal invasion (p = 0.007), absence of ER (p = 0.006) and of PR (p = 0.002), c-erb-B2 expression (p = 0.008), p53 expression (p = 0.007) and tumor size (p = 0.01). An expression of Ki67 in 20% or more of tumor cell nuclei, on the other hand, correlated significantly with histological grade 3 (p < 0.0001), nuclear grade 3 (p < 0.0001), absence of ER (p < 0.0001) and of PR (p < 0.0001), c-erb-B2 expression (p < 0.0001), p53 expression (p < 0.0001) and tumor size (p = 0.0005), but not with nodal invasion. CONCLUSION: Although flow cytometry provides additional data (association with nodal invasion), the study of Ki67 expression emerges from this study as a simple, inexpensive and reliable method to study the proliferation rate of breast cancer.

Tamoxifen therapy in breast cancer: do apolipoprotein E genotype and menopausal state affect plasma lipid changes induced by the drug?

OBJECTIVE: This study examines the lipid profile change produced in response to tamoxifen (TAM) treatment, and its possible relationship with both apolipoprotein E genotype and menopausal state in patients with breast cancer. METHODS: Blood samples were collected from 86 Spanish women with breast cancer before initiating TAM treatment and in the following 6, 12 and 18 months of treatment. Plasma lipid levels (total cholesterol, triglycerides, HDL-cholesterol and LDL-cholesterol) were determined using an automatic analyzer. Genotypes for apolipoprotein E (ApoE) were identified by PCR-RFLP using the HhaI enzyme. RESULTS: In all patients, significant reductions in total cholesterol and LDL-cholesterol concentrations and a significant increase in triglyceride concentrations were observed after 6, 12, and 18 months of TAM treatment compared to baseline (p<0.01 for each time point). In the subset of APOE4-negative patients, triglyceride concentrations also significantly increased after 6, 12, and 18 months of treatment (p=0.019, p=0.045, p=0.001, respectively), while APOE4-positive patients showed no significant lipid changes at 12 and 18 months. However, after 18 months of TAM treatment the overall triglyceride concentrations had risen by 24.75% in APOE4-negative patients vs 29.9% in APOE4-positive patients. In postmenopausal women, significant reductions in total cholesterol, LDL-cholesterol and LDL/HDL ratios were observed at each time point (p<0.020 for each). CONCLUSIONS: TAM treatment induced similar plasma triglyceride increases in patients with positive or negative APOE genotype. Compared to premenopausal patients, postmenopausal breast cancer patients showed a more beneficial lipid profile change in response to treatment.

Relationship between genotypes Sult1a2 and Cyp2d6 and tamoxifen metabolism in breast cancer patients.

Tamoxifen is a pro-drug widely used in breast cancer patients to prevent tumor recurrence. Prior work has revealed a role of cytochrome and sulfotransferase enzymes in tamoxifen metabolism. In this descriptive study, correlations were examined between concentrations of tamoxifen metabolites and genotypes for CYP2D6, CYP3A4, CYP3A5, SULT1A1, SULT1A2 and SULT1E1 in 135 patients with estrogen receptor-positive breast cancer. Patients were genotyped using the Roche-AmpliChip® CYP450 Test, and Real-Time and conventional PCR-RFLP. Plasma tamoxifen, 4-hydroxy-tamoxifen, N-desmethyl-tamoxifen, endoxifen and tamoxifen-N-oxide were isolated and quantified using a high-pressure liquid chromatography-tandem mass spectrometry system. Significantly higher endoxifen levels were detected in patients with the wt/wt CYP2D6 compared to the v/v CYP2D6 genotype (p<0.001). No differences were detected in the remaining tamoxifen metabolites among CYP2D6 genotypes. Patients featuring the SULT1A2*2 and SULT1A2*3 alleles showed significantly higher plasma levels of 4-hydroxy-tamoxifen and endoxifen (p = 0.025 and p = 0.006, respectively), as likely substrates of the SULT1A2 enzyme. Our observations indicate that besides the CYP2D6 genotype leading to tamoxifen conversion to potent hydroxylated metabolites in a manner consistent with a gene-dose effect, SULT1A2 also seems to play a role in maintaining optimal levels of both 4-hydroxy-tamoxifen and endoxifen.

Tratamiento radical del cáncer de mama / Radical treatment of the breast cancer

Posiblemente, si a lo largo de los 100 años de este siglo XX que termina, nos hubieran encargado este capítulo en diferentes libros de mastología, los criterios expuestos difícilmente hubieran cambiado tanto con otro tema cualquiera. En la primera parte del siglo nos hubiéramos sentido orgullosos de la mastectomía que realizábamos. Por fin podían presentarse resultados satisfactorios en el tratamiento del cáncer de mama con una cirugía radical, que apoyada en la filosofía halstediana, mejoraban incluso, al apoyarla con otras terapéuticas complementarias. Quizas el entusiasmo de esos resultados crecientes y la hegemonía de los principios anatomicistas halstedianos, llevaron la cirugía a su extremo más radical y en la mitad del siglo nos congratulábamos de poder ofertar "más" a nuestras enfermas y llégo la hora de las mastectomías ampliadas. Siempre nos gusto comparar la evolución de la cirugía del cáncer de mama, como de cualquier cirugía oncológica, o tantos criterios no sólo científicos, sino humanos, filosóficos o religiosos, al trayecto de un péndulo, que es este momento llega a su extremo más radical para iniciar su descenso. Y ese descenso de la mano de un mejor conocimiento de la historia natural del cáncer de mama, del inicio de la era biológica y el camino nuevo de la inmunología en las relaciones huesped-tumor, y se apoyó entonces, en lo Fisher llamó su teoría alternativa

Carcinoma oculto / Occult carcinoma

El carcinoma oculto es una rara forma de presentación del cáncer mamario, que se manifiesta por la aparición de enfermedad metastásica en los ganglios axilares, sin que pueda demostrarse tumor en la glándula.La primera descripción de este proceso la hizo Halsted en 1907, al hacer referencia a tres observaciones de pacientes a la que efectuó extirpación de unos ganglios axilares de aspectos neoplásico, al conocer por el estudio histológico que eran de origen mamario no realizó ningún gesto quirúrgico sobre la axila, apareciendo en las mamas de dos de las pacientes sendos tumores en los siguientes dos años y medio. Desde entonces, no llegan a 400 los casos publicos que se recogen en el Internationl Index Medicus, observándose una franca disminución de la incidencia conforme ha ido mejorando la calidad de la mamografía. Como certeramente apunta Uriburu, la mayoría de los casos ocultos de la era premamográfica hoy serían considerados como "no palpables"