In this work we analyzed data obtained from case-history of 36 patients operated in Hospital for tumors, Zagreb in period 2006 till 2007 year. Ductal breast cancer in situ (DCIS) were diagnosed in 24 patients while in 12 patient's diagnosis was ductal micro invasive breast cancer. Aim of thesis was to define expression of polyclonal and monoclonal anti-laminin antibodies on basement membrane of duct's in breast cancer using immunohistochemical method. We investigated whether loss of laminin in basement membrane can be a predictive marker for micro invasiveness. We also investigated association between prognostic factors as age of patients, tumor differentiation stage, steroid hormone receptors and HER2 status with anti-laminin expression and micro invasion appearance. Average age of patients was 56.5 years. The results showed that polyclonal anti-laminin is an important predictive factor of micro invasion appearance in DCIS (p=0,00026) comparing to monoclonal anti-laminin (p=0,23765) (p<0,05 ). Other prognostic factors had no significance in micro invasion, neither the importance towards laminin expression on basement membrane. Polyclonal anti-laminin found to be a good indicator of the basement membrane integrity and can be used as predictive marker of micro invasion appearance at DCIS.