PROS1 and thyroid gland papillary carcinoma: Notably, AXL is highly expressed in undifferentiated, medullary, and papillary thyroid carcinomas.[27] PROS1 expression is significantly correlated with lymph node staging in patients with PTC, and downregulation of PROS1 inhibits PTC cell proliferation and migration.[28] While these findings underscore the relevance of TAM receptor signaling in PTC, many questions remain unanswered, particularly regarding the full extent of TAM receptor signaling in the PTMC tumor microenvironment.