ESR1 and colon carcinoma: JH Lagendijk et al [10] have also observed in their study that although the immunostaining patterns show a considerable overlap, the breast carcinomas were typically positive for GCDFP-15 and often for ER, and negative for vimentin whereas colonic carcinomas showed prominent positivity for CEA and CK20, while no staining was seen for ER and vimentin.