Chromosomal Aberrations in Breast Cancer Patients in West Bengal, India

Breast cancer is the most frequent malignancy among women. Since genetic factors such as BRCA1 and BRCA2 as well as reproductive history constitute 30% of the cause, environmental exposure may play a significant role in the development of breast cancer. Likewise, the relevant enzymes involved in the biotransformation of xenobiotics (from tobacco smoke, diet or other environmental sources) might play a role in breast carcinogenesis. We have carried out cytogenetic studies, using the Gbanding technique in peripheral blood lymphocytes of 10 patients affected by breast carcinoma. A variety of chromosomal aberrations including aneuploidy, polyploidy, cluster of cells, acrocenteric associations, chromosomal breaks and gaps were seen in the peripheral blood leucocytes of the patients. The frequency of aberrant metaphases varied from 5% to 69% in cultured leucocytes. The frequency of aneuploidy in sporadic breast cancer was 43% to 69% and in hereditary breast cancer was 65%to 68 %( P= 0.25). The frequency of other aberrations like polyploidy, cluster of cells formation and acrocentric association was significantly found in hereditary breast cancer compared to sporadic breast cancer. Random chromosomal breaks and gaps was found significantly in hereditary breast cancer (p<0.0001).Chromosomal aberrations were not seen in controls. Mitotic index in breast cancer was higher than in controls (P = 0.0038). The present study lays the emphasis on initiating karyotyping as screening recommendations for detecting early age of onset in Hereditary Breast Cancer (HBC) because molecular analysis is a tedious and very costly technique. Address correspondence to: Dr. Ajanta Halder Phone: +91983019673 Fax: +9133 2475 4351 E-mail: [email protected], INTRODUCTION Cancer research in the past 20 years has generated a rich and complex body of knowledge, revealing cancer to be a disease involving dynamic changes in the genome. The genomes of tumour cells are invariably altered at multiple sites, having suffered disruption through lesions as subtle as point mutations and as obvious as changes in chromosome. The early notion that cancer was caused by mutations in genes critical for the control of cell growth implied that genome stability is important for preventing oncogenesis (Charles.Burnicardi 2004). Genomic instability in the peripheral blood lymphocytes has been correlated with tumour progression. Various reports indicate a significant increase in the chromosomal aberrations in peripheral blood lymphocytes of cancer patients with solid tumours. PBLs of patient with breast cancer and other solid tumours show simple chromosomal lesions that may be a stable marker in cancer cells. Hence, it is proposed that lymphocyte may be used as a surrogate tissue model for studying genomic instability in case of solid tumours and the frequency of chromosomal aberrations in PBLs can be used as a predictor of cancer risk (Harsimaran et al. 2009). Breast Carcinoma is among the most common and lethal malignancies in women. Currently, India reports roughly 1,00,000 cases annually (Bagchi 2008). As against as estimated 48,710 women who died of breast cancer in 2007, the number breached the 50,000 mark in 2010. The figure for the year 2011 was put at 50,821 (Sinha 2011). In the present study, our aims were to 1) To detect chromosomal aberrations (CAs) in Breast Cancer patients and compare it with controls (healthy individuals). 2) To compare chromosomal aberrations found in Sporadic Breast Cancer (SBC) and Hereditary Breast Cancer (HBC) and its key role in early breast cancer detection, prevention and treatment. MATERIAL AND METHODS The present study was carried out as a single centre study and single blinded study over a period of 1 year from July 2010 to June 2011. The study was carried out involving the Department of General Surgery, Department of Genetics and Pathology Department of Ramakrishna Mission Seva Pratishthan, V.I.M.S, Kolkata. The © Kamla-Raj 2013 Int J Hum Genet, 13(1): 1-6 (2013)