Transcriptome analysis in early stage Breast cancer using next generation sequence Analysis

Abstract

Breast cancer is one of the most common cancers among women. In India, the incidence newlinerate is 13 per 100,000 women per year in the rural areas and 27 per 100,000 per year in the newlineurban areas (NCRP, 2010 (http://ncdirindia.org). Breast cancer is primarily categorized into newlinenon-invasive ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC). DCIS newlineis termed as a non-obligatory precursor of malignant lesions [Figure 1]. Retrospective newlinestudies have indicated a 10-fold increased risk of developing IDCs in women with a history newlineof DCIS than women with no previous DCIS history [1]. Systematic review and metaanalysis newlineof retrospective and prospective pure DCIS patient studies revealed that there is newline35% to 55% chance of invasive carcinoma recurrence in case of DCIS patients after ~15 newlineyears of diagnosis, whereas ~28% recurrence is reported in case of DCIS surgical excision newline[2]. There is substantially higher DCIS incidence in the past decade, probably due to newlineimprovements in early diagnosis. It is a predicament for clinicians to predict the prognosis newlinereliably [3]. Long term follow-up studies report suggests that even low-risk DCIS subtypes newlinecan recur after 30 years [3]. Figure 1. Schematic representation of ductal carcinoma in situ and advance stage tumors where pink spheres represent myoepithelial cells, and green spheres represents cancerous cells With the advent of Next Generation Sequencing (NGS) techniques, the global expression profile of mRNAs, long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) is xtensively investigated in various cancers. Multiple studies have reported differential newlinemRNA expression profiles in early and advanced-stage breast cancers. Major subtypes of breast cancers, i.e., Luminal A, Luminal B, Her2+, Basal, and normal-like, can be readily newlinestratified based on breast cancer gene expression profile [4, 5]. LncRNAs and miRNAs are reported to play a crucial role in tumorigenesis. Functional characterization of certain lncRNAs such as UCA1, GAS5, and XIST have established them as breast canceras