Small aggregates of tumor cells extending or detaching from the bulk tumor and entering the adjacent stroma have been detected at the invasive fronts of human tumors such as colon carcinoma, breast carcinoma, papillary thyroid carcinoma, cervical carcinoma etc. This was found to be concomitant with reduced expression of E-cadherin, selective loss of basement membrane and/or increased expression of Vimentin etc. Interestingly enough, it was found that often cancer cells undergoing EMT do not show a complete conversion, rather they pass through EMT at different extents. This evidence concerns the gene CDH1 and breast carcinoma.