Functional analysis of GPRC5a in different carcinomas indicated that RAI3 has pleiotropic effects and might confer resistance to Gemcitabine in pancreatic cancer, however the ligand of GPRC5a remains elusive [12], but GPRC5a overexpression might lead to a reduction of EGFR levels [13–16]. Here, GPRC5A is linked to familial pancreatic carcinoma.