RB1 and malignant colon neoplasm: SFN is reported to affect survival pathway by hyperphosphorylation of Rb protein (anti-apoptotic in un-phosphorylated form) in colon cancer cells, and has inhibited cyclin D1 in pancreatic cancer cells [22,23], whereas, cyclin D1-induced Rb overexpression has been found to be upregulated in pulmonary carcinoids [24].