RAP1GDS1 and breast cancer: RAP1GDS1 (RAP1, GTP‐GDP dissociation stimulator (1), also known as SmgGDS, is an atypical guanine nucleotide exchange factor (GEF) that is involved in the regulation of both cell migration and proliferation, and is overexpressed in many cancer types, including non‐small cell lung carcinoma,2, 3 breast cancer,3 prostate cancer,4 and pancreatic cancer.3