Peanut lectin (PNA) is an identical tetrameric carbohydrate free protein with MW of 110 kDa. Thomsen-Friedenreich antigen, T-antigen (Galβ1, 3GalNAc) is present on blood group M &N glycoproteins (after removal of sialic acid with neuraminidase), glyconjugates (Mucin type), gangliosides and many glycolipids. T antigen is rarely expressed on normal coloncytes whereas cells of malignant, premalignant cells express this antigen. Peanut lectin has widely been used to detect T antigen in malignant and premalignant cells. Peanut lectin contains one atom of Ca++ and Mg++ per unit.