Rab27A and Rab27B expression were significantly related to patient gender (P = 0.007 and 0.002, respectively) and histologic type (P = 0.009 and < 0.001, respectively), but not to patient age, smoking history, surgical method, or tumor node metastasis stage.
RAB27B-activated secretion of stem-like tumor exosomes delivers the biomarker microRNA-146a-5p, which promotes tumorigenesis and associates with an immunosuppressive tumor microenvironment in colorectal cancer.
Reverse transcription-polymerase chain reaction (RT-PCR), western blot, and immunohistochemistry (IHC) analysis were used to examine Rab27A and Rab27B expression in human CRC cell lines and primary tumors.
Positive staining of Rab27B was significantly associated with tumor size (P = 0.006), mitotic index (P = 0.013), Armed Forces Institute of Pathology Miettinen risk classification (P = 0.002), and tumor grade (P = 0.021).
Survival analyses revealed that patients with Rab27A(+) or Rab27B(+) tumors had significantly reduced overall survival compared with that of patients with Rab27A(-) or Rab27B(-) tumors (P = 0.015 and P = 0.005, respectively).
BACKGROUND Secretory GTPases like Rab27B control vesicle exocytosis and deliver critical proinvasive growth regulators into the tumor microenvironment.