MTOR and pancreatic neoplasm: In vivo mouse experiments demonstrated that rapamycin exhibited superior antitumor activity to S-1 (a metabolically activated prodrug of 5-fluorouracil) and another mTOR inhibitor, everolimus, while its efficacy was similar to that of gemcitabine plus paclitaxel (which was used instead of nab-paclitaxel due to concerns about allergic reactions in mice to human albumin) in a mouse model of pancreatic cancer using human pancreatic cancer cell line-derived organoids.