RB1 and pancreatic endocrine carcinoma: Prior studies have shown the loss of pRb protein expression in 67–80% of GEP-NEC (Li et al. 2008, Busico et al. 2020), 33–55% of pancreatic NEC (Hijioka et al. 2017, Konukiewitz et al. 2018) and 56% of colorectal (CR)-NEC (Takizawa et al. 2015).