TRPS1 and skin basal cell carcinoma: As TRPS1 is a nuclear protein [15], we examined the cellular localization of TRPS1 and Cath-D in ER+ BCC lines (T47D, MCF7 and BT474), immortalized human breast epithelial cells (HMT3522-S1) and human breast fibroblasts (HMF) (Fig. 3A).