Immunotherapy is a recent hotspot in lung cancer research. The ability of the immune system to recognize tumor cells as foreign is restricted through the expression of certain cell-surface molecules such as the major histocompatibility complex (MHC) molecules. The alteration in MHC class II antigens is an event that occurs frequently on primary and metastatic cancer. Therefore, we described the expression of MHC class II in lung cancer cell lines and patient tissues.
We studied MHC II (DP, DQ, DR) (CR3/43, Abcam) protein expression in 55 non-small cell lung cancer (NSCLC) cell lines, 42 small cell lung cancer (SCLC) cell lines and 278 lung cancer patient tissues by immunohistochemistry (IHC).
Seven (12.7%) NSCLC cell lines were positive for MHC class II. No SCLC cell lines were found to be MHC II positive. MHC class II was detected in 139 lung cancer samples from the Hirsch Lab. Twenty-one (31.3%) samples stained positive for MHC class II on tumor cells, and 38 (56.7%) had positive MHC class II expression on tumor infiltration lymphocytes (TILs) in NSCLC. There was no positive MHC class II staining on SCLC tumor cells. MHC class II on TILs in SCLC was significant lower than MHC II on TILs in NSCLC (P
MHC class II was expressed in both NSCLC cell lines and tissues. However, MHC class II was absent in SCLC cell lines and tissue tumor cells. Loss of expression of MHC II on SCLC tumor cells may be a means of escaping anti-cancer immunity. MHC class II expression on TILs was correlated with good prognosis in NSCLC patients.
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This project was supported by IASLC Young Investigator Award, the Pia and Fred R. Hirsch Endowed Chair at the University of Colorado, and Young Program of Shanghai Health Bureau.
All authors have declared no conflicts of interest.