Control of T-cell–mediated immune response by HLA class I in human pancreatic carcinoma

E Ryschich, T Nötzel, U Hinz, F Autschbach… - Clinical cancer …, 2005 - AACR
E Ryschich, T Nötzel, U Hinz, F Autschbach, J Ferguson, I Simon, J Weitz, B Fröhlich…
Clinical cancer research, 2005AACR
Purpose: Cell surface HLA class I molecules present peptides derived from human cellular
proteins to T cells. In the present study, we investigated the expression of HLA class I in
human pancreatic carcinoma. Experimental Design: The expression of HLA class I antigen
and the extent of tumor infiltration by T cells were investigated in 46 primary tumors and in
14 metastases of pancreatic cancer by standard immunohistochemistry. Results: The locus-
specific expression of HLA I was reduced in 61% of primary tumors and in 93% of …
Abstract
Purpose: Cell surface HLA class I molecules present peptides derived from human cellular proteins to T cells. In the present study, we investigated the expression of HLA class I in human pancreatic carcinoma.
Experimental Design: The expression of HLA class I antigen and the extent of tumor infiltration by T cells were investigated in 46 primary tumors and in 14 metastases of pancreatic cancer by standard immunohistochemistry.
Results: The locus-specific expression of HLA I was reduced in 61% of primary tumors and in 93% of metastases. The total loss of this molecule complex was detected in 6% of primary tumors and in 43% of metastases. Pancreatic carcinoma and peritumoral tissue showed a significantly higher infiltration by CD3+, CD4+, and CD8+ T-cells compared with the tumor-distant pancreatic tissue. The negative expression of HLA class I was uniformly accompanied by a low density of tumor-infiltrating cytotoxic T-cells whereas the HLA class I–positive tumors were characterized by a substantial lymphocyte accumulation. However, the infiltration by cytotoxic T-cells was not correlated with the density of tumor cells. Patients with a high accumulation of cytotoxic cells showed a longer median survival.
Conclusions: Pancreatic carcinoma frequently induces a cellular immune response that results in intratumoral and peritumoral T-cell infiltration. The expression of HLA class I is frequently lost in pancreatic carcinoma, which represents an effective mechanism to escape the tumor infiltration by cytotoxic T-cells. However, the infiltration by cytotoxic cells represents a favorable prognostic sign in pancreatic cancer patients.
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