How do you differentiate CA in situ from invasive CA-

Ans. is `a' i.e., Penetration of basement membrane o Dysplasia, carcinoma in situ and invasive carcinoma represent the three steps in the progression of many malignant neoplasms of epithelial tissues. Dysplasia Disordered growth with lack of uniformity of individual cells. Carcinoma in situ when dysplastic changes involve entire thickness of epithelium, but the lesion remains confined to the normal tissue and there is no penetration of basement membrane. Carcinoma in situ means cancer in place. Invasive carcinoma ---> There is penetration of basement membrane and tumor cells move beyond the normal confines.