Globally the breast cancer is the most common cancer in women than other cancers. Recently, molecular studies urge for these familial syndromes to dig out the etiology, but several defective tumor suppressor genes been associated with familial breast cancer. Mainly, the BRCA–I gene at 17q21 as tumor suppressor gene, since a single mutation in BRCA–1 dramatically increases a woman‘s risk for breast cancer. Here we analyze the genetic instability in breast cancer tissue compared with normal tissues from the same individual through cloning and AP–PCR (Arbitrary primed polymerase chain reaction) using 4 different primers. Among these OPC4 showed presence of and variation in the genetic set up of cancer tissue and further it purified and cloned in to a T– tailed vector viz. pTZ57R/T. Presence of amplified DNA fragments was indicating homozygous insertion of 1270 bp observed in breast cancer plasmid.