Selective loss of beta 2-microglobulin mRNA in human colon carcinoma.
Expression of MHC class I antigens requires the intracellular assembly of HLA-A,B,C H chains and beta 2-microglobulin (beta 2m). We have investigated the expression of free H chain, beta 2m, and their mRNAs in tissue sections of colon carcinomas that were defective for the native two-chain molecule. In all of these tumors, beta 2m protein and mRNA were found to be completely absent from the neoplastic cells, whereas free H chains and their respective mRNAs were present in abundance in the tumor cell cytoplasm. The selective abrogation of beta 2m expression represents a unique mechanism leading to a complete loss of class I antigen surface expression in vivo.
Momburg
F
F
Institute of Pathology, University of Heidelberg, Federal Republic of Germany.
Koch
S
S
D002277:Carcinoma / Q000235:genetics*; D003110:Colonic Neoplasms / Q000235:genetics*; D006680:HLA Antigens / Q000235:genetics*; D006801:Humans; D007124:Immunoenzyme Techniques; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics*; D001613:beta 2-Microglobulin / Q000235:genetics*
D006680:HLA Antigens; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D001613:beta 2-Microglobulin