Tumor-infiltrating lymphocytes (TILs) in colorectal cancer liver metastases (CLMs) have been associated with more favorable patient outcomes, but whether MHC class I (MHC-I) expression on cancer cells impacts prognosis is uncertain. Immunohistochemistry was performed on a tissue microarray of 158 patients with CLMs who underwent partial hepatectomy with curative intent. Using the antibody HC-10, which detects HLA-B and HLA-C antigens and a minority of HLA-A antigens, MHC-I expression was correlated with β-2 microglobulin (β2m) (r=0.7, p<0.001), but not to T cell density (r<0.32). The median follow up for survivors was 9.7 years. High levels of MHC-I expression in tumors concomitant with high T-cell infiltration (CD3, CD4, or CD8) best identified patients with favorable outcomes, compared to patients with one or neither of these immune features. The median overall survival (OS) of patients with MHC-IhiCD3hi tumors (n=31) was 116 months compared to 40 months for the others (p=0.001), and the median time-to-tumor recurrence (TTR) was not reached compared to 17 months (p=0.008). By multivariate analysis, MHChiCD3hi was associated with OS and TTR independently of standard clinicopathological variables. An immune score that combines MHC-I expression and TIL density may be a valuable prognostic tool in the treatment of patients with CLM.
- Received October 14, 2013.
- Revision received January 20, 2014.
- Accepted February 10, 2014.
- Copyright © 2014, American Association for Cancer Research.