Introduction: In India breast cancer is the 2nd most common cancer in women after cervical cancer and is associated with high mortality and morbidity. Role of IL-10 in cancer though, well accepted, is vaguely understood. IL-10 is known to exhibit both pro and anti-tumour activities. Polymorphism in interleukin genes are thought to influence the expression or function of these proteins. Hence our study was designed to evaluate the role of low penetrant interleukin-10 (IL10) gene and its influence on tumorigenesis.