PDCD1 and neoplasm: According to Watek et al., the potential pro-neoplastic mechanism of Gaucher cells and expression of programmed cell death protein 1 (PD-1) in tumor-associated macrophages is as follows: the accumulation of glucocerebroside in macrophages and expression of PD-1 on their surface affects the survival of tumor cells, and the cytokines they secrete increase their invasiveness and promote angiogenesis and the ability to form metastases.