High expression of HLA-E in colorectal carcinoma is associated with a favorable prognosis.

Abstract

BACKGROUND:

Human Leukocyte Antigen (HLA)-E is a non-classical class I HLA molecule that can be stabilized by ligands donated by other classical (HLA-A, -B, -C) and non-classical (HLA-G) family members. HLA-E engages a variety of immune receptors expressed by cytotoxic T lymphocytes (CTLs), Natural killer (NK) cells and NK-CTLs. In view of the opposing outcomes (activation or inhibition) of the different HLA-E receptors, the preferred role (if any) of HLA-E expressed in vivo on tumor cells remains to be established.

METHODS:

Taking advantage of MEM-E/02, a recently characterized antibody to denatured HLA-E molecules, HLA-E expression was assessed by immunohistochemistry on an archival collection (formalin-fixed paraffin-embedded) of 149 colorectal primary carcinoma lesions paired with their morphologically normal mucosae. Lymphoid infiltrates were assessed for the expression of the HLA-E-specific, inhibitory, non-rearranging receptor NKG2A.

RESULTS:

High HLA-E expression did not significantly correlate with the expression of classical HLA-B and HLA-C molecules, but it did correlate with high expression of its preferential ligand donor HLA-A. In addition, it correlated with lymphoid cell infiltrates expressing the inhibitory NKG2A receptor, and was an independent predictor of good prognosis, particularly in a subset of patients whose tumors express HLA-A levels resembling those of their paired normal counterparts (HLA-A). Thus, combination phenotypes (HLA-Elo-int/HLA-AE and HLA-Ehi/HLA-AE) of classical and non-classical class I HLA molecules mark two graded levels of good prognosis.

CONCLUSIONS:

These results suggest that HLA-E favors activating immune responses to colorectal carcinoma. They also provide evidence in humans that tumor cells entertain extensive negotiation with the immune system until a compromise between recognition and escape is reached. It is implied that this process occurs stepwise, as predicted by the widely accepted 'immunoediting' model.

• Authors: Maria Benevolo, Marcella Mottolese, Elisa Tremante, Francesca Rollo, Maria Grazia Diodoro, Cristiana Ercolani, Isabella Sperduti, Elisa Lo Monaco, Maurizio Cosimelli, Patrizio Giacomini
• Journal: Journal of translational medicine (J Transl Med) Vol. 9 Pg. 184 (Oct 27 2011) ISSN: 1479-5876 [Electronic] England
• PMID: 22032294 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies
• CD8 Antigens
• HLA-E antigen
• Histocompatibility Antigens Class I
• NK Cell Lectin-Like Receptor Subfamily C

Topics

• Adult
• Aged
• Aged, 80 and over
• Alleles
• Antibodies (immunology)
• CD8 Antigens (immunology)
• Colorectal Neoplasms (diagnosis, immunology, pathology)
• Female
• Histocompatibility Antigens Class I (genetics, immunology)
• Humans
• Immunohistochemistry
• Intestinal Mucosa (immunology, pathology)
• Kaplan-Meier Estimate
• Male
• Middle Aged
• Models, Immunological
• Multivariate Analysis
• NK Cell Lectin-Like Receptor Subfamily C (immunology)
• Neoplasm Staging
• Paraffin Embedding
• Prognosis
• Tissue Fixation