NR4A1 and breast cancer: In a similar way, GRPR has been shown to be overexpressed in several tumors.(28-30) High expression of GRPR protein was evidenced in breast cancer, with tumors positive for hormonal receptors expressing higher GRPR mRNA levels than normal tissues.(28) In anal canal carcinomas, for example, GRPR presented a diffuse and homogenous pattern of expression compared to control samples, suggesting a possible role of this receptor in carcinogenesis.(29)