Comparative proteomic analysis of ductal and lobular invasive breast carcinoma.

Breast cancer is the second most common cancer worldwide and the first among women. Invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) are the two major histological subtypes, and the clinical and molecular differences between them justify the search for new markers to distinguish them. As proteomic analysis allows for a powerful and analytical approach to identify potential biomarkers, we performed a comparative analysis of IDC and ILC samples by using two-dimensional electrophoresis and mass spectrometry. Twenty-three spots were identified corresponding to 10 proteins differentially expressed between the two subtypes. ACTB, ACTG, TPM3, TBA1A, TBA1B, VIME, TPIS, PDIA3, PDIA6, and VTDB were upregulated in ductal carcinoma compared to in lobular carcinoma samples. Overall, these 10 proteins have a key role in oncogenesis. Their specific functions and relevance in cancer initiation and progression are further discussed in this study. The identified peptides represent promising biomarkers for the differentiation of ductal and lobular breast cancer subtypes, and for future interventions based on tailored therapy.

PDIA3 and PDIA6 gene expression as an aggressiveness marker in primary ductal breast cancer.

Changes in the expression of the protein disulfide isomerase genes PDIA3 and PDIA6 may increase endoplasmic reticulum stress, leading to cellular instability and neoplasia. We evaluated the expression of PDIA3 and PDIA6 in invasive ductal carcinomas. Using reverse transcription-quantitative polymerase chain reaction, we compared the mRNA expression level in 45 samples of invasive ductal carcinoma with that in normal breast samples. Increased expression of the PDIA3 gene in carcinomas (P = 0.0009) was observed. In addition, PDIA3 expression was increased in tumors with lymph node metastasis (P = 0.009) and with grade III (P < 0.02). The PDIA6 gene showed higher expression levels in the presence of lymph node metastasis (U = 99.00, P = 0.0476) and lower expression for negative hormone receptors status (P = 0.0351). Our results suggest that alterations in PDIA3/6 expression levels may be involved in the breast carcinogenic process and should be further investigated as a marker of aggressiveness.

Proteomic analysis of non-tumoral breast tissue.

Breast cancer is a complex and heterogeneous disease. In spite of the advances made in recent decades, a better understanding of the intrinsic mechanisms of this disease is crucial. The development of new biomarkers is absolutely necessary to improve diagnosis and prognosis. Research using the proteomic approach has generated interesting results; however, the complexity of the mammary gland and of breast tumors remains a major limitation to the development of new markers. An initial step is to characterize non-tumoral human breast tissue. We present data from classical proteomic analysis based on 2-D electrophoresis and peptide mass fingerprinting identification, which were performed on six non-tumoral samples from patients with invasive ductal breast carcinomas. Forty-four different proteins from 70 spots were identified and classified according to their biological function. Cytoskeleton and associated proteins represent the largest class (30%) followed by the proteins with binding function (27%). Several of the proteins have been described in breast tumors, such as vimentin, endoplasmin, small heat shock beta-6, disulfide isomerase and some cell growth, and proliferation regulators, suggesting the importance of including data on the characterization of non-tumoral breast and to studies on differential expression in cancer tissue.

Patterns of DNA copy number changes in sentinel lymph node breast cancer metastases.

The sentinel lymph node (SLN) is considered to be the first axillary node that contains malignant cells in metastatic breast tumors, and its positivity is currently used in clinical practice as an indication for axillary lymph node dissection. Therefore, accurate evaluation of the SLN for the presence of breast metastatic cells is essential. The main aim of our study is to characterize the genomic changes present in the SLN metastatic samples with the ultimate goal of improving the predictive value of SLN evaluation. Twenty paired samples of SLN metastases and their corresponding primary breast tumors (PBT) were investigated for DNA copy number changes using comparative genomic hybridization (CGH). Non-random DNA copy number changes were observed in all the lesions analyzed, with gains being more common than losses. In 75% of the cases there was at least one change common to both PBT and SLN. The most frequent changes detected in both lesions were gains of 1pter-->p32, 16, 17, 19, and 20 and losses of 6q13-->q23 and 13q13-->q32. In the PBT group, alterations on chromosomes 1, 16, and 20 were the most frequent, whereas chromosomes 1, 6, and 19 were the ones with the highest number of changes in the SLN metastatic group. A positive correlation was found between the DNA copy number changes per chromosome in each of the groups. Our findings indicate the presence of significant DNA copy number changes in the SLN metastatic lesions that could be used in the future as additional markers to improve the predictive value of SLN biopsy procedure.

Genetic polymorphisms in oestrogen metabolic pathway and breast cancer: a positive association with combined CYP/GST genotypes.

The cytochrome P450 family (CYPs) and the glutathione S-transferase (GSTs) enzymes play an important role in the metabolism of environmental carcinogens and of oestrogen and can affect breast cancer risk. In this study we examine the role of the genes CYP1A1, CYP17, CYP2D6, GSTM1, GSTP1 and GSTT1 in breast cancer risk in Brazilian women. The study population consisted of 102 incident breast cancer cases and 102 healthy controls. Genotyping analyses were performed by PCR-based methods. A significant finding was observed between GSTP1 Ile-Val polymorphism and breast cancer risk (OR = 1.81; CI 95% = 1.04-3.16). A significant association was observed between women with 0-2 risk genotypes and those with 4 or more risk genotypes (OR = 2.42; CI 95% = 1.13-5.18) when the potential combined effects of the risk genotypes were examined. No significant differences between cases and controls were found correlating the genotypes and the clinical-histopathological parameters. In conclusion, in our population only GSTP1 was associated with breast cancer risk. However, when the genes were tested in combination, a significant association in the breast cancer risk was observed.

Long-term oncological results of breast conservative treatment with oncoplastic surgery.

Oncoplastic surgery combining breast conservative treatment (BCT) and plastic surgery techniques may allow more extensive breast resections and improve aesthetic outcomes, but no long-term oncological results have been published. Long-term oncologic results of 148 consecutive BCT with concomitant bilateral plastic surgery have been analysed and were compared to historical data of BCT trials. Median follow-up was 74 months. Complete excision was obtained in 135 patients (91%); focally involved margins in 8 (5%); and close (<2 mm) margins in 5 (3%). Five patients developed ipsilateral recurrence (3%), 19 (13%) developed distant metastasis and 11 patients died (7.53%). Patients with tumours larger than 2 cm were at greater risk of local recurrences and distant metastasis. Long-term oncologic results of BCT with oncoplastic surgery are comparable with the results of BCT randomized trials.

Clonal chromosomal alterations in fibroadenomas of the breast.

A cytogenetic study on short-term cell cultures from 10 fibroadenomas of the breast is reported. Clonal chromosomal alterations were observed in all cases analyzed, involving preferentially chromosomes X, 12, 14, 20, and 22. Normal karyotypes were found in 34.9% of the cells. The present findings are discussed together with the reports on fibroadenomas and other benign lesions of the breast described in the literature. Although no specific chromosome abnormality to date can be attributed to a particular type of benign breast pathology, some recurrent alterations are starting to emerge and may characterize these benign breast lesions, differentiating them from their malignant counterparts.