The prognostic and clinicopathological roles of microsatellite instability, PD-L1 expression and tumor-infiltrating leukocytes in familial adenomatous polyposis.

BACKGROUND

Microsatellite instability, programmed death-ligand 1 and tumor-infiltrating leukocytes are prognostic biomarkers in colorectal cancer but unknown toward familial adenomatous polyposis.

AIM

To investigate the prognostic and clinicopathological roles of microsatellite instability, programmed death-ligand 1 and tumor-infiltrating leukocytes in familial adenomatous polyposis.

METHODS

Clinical data and paraffin embedded tissues from 45 familial adenomatous polyposis patients were collected. Microsatellite instability was detected by immunohistochemistry and polymerase chain reaction. Programmed death-ligand 1 was detected by immunohistochemistry. Tumor-infiltrating leukocytes comprising CD8 T cells, M1 and M2 tumor associated macrophages, CD56 and CD56 natural killer cells were analyzed using multiple fluorescence immunohistochemistry.

RESULTS

Microsatellite instability high was noted in 6 samples but not associated with overall survival or progression-free survival. Programmed death-ligand 1 is negative on tumor cells but positive on tumor-infiltrating leukocytes, and positive programmed death-ligand 1 expression on tumor-infiltrating leucocytes is associated with overall survival. Low CD56 natural killer cell infiltration was associated with longer progression-free survival and was an independent prognostic factor in FAP.

CONCLUSION

For familial adenomatous polyposis, microsatellite instability high can be found but has no correlation with prognosis; programmed death-ligand 1 on tumor-infiltrating leukocytes is related with overall survival; CD56 natural killer cell is an independent prognostic factor associating with longer progression-free survival.