Overall major histocompatibility complex class I expression is not downregulated in cervix cancer, as detected by immunoelectron microscopy.

Downregulation of major histocompatibility complex (MHC) class I molecules in cervix cancer has been proposed as a mechanism for cancer cells to escape immunodetection. By means of light microscopic immunohistochemistry, it has been shown that in 20-70% of cervix cancers MHC class I is downregulated. We have reinvestigated this phenomenon by quantitative immunogold analysis of MHC class I labeling on the plasma membrane of cervix epithelial cells in ten human squamous cancers and ten normal human cervices. We have not found a statistically significant difference in MHC class I expression between normal and cancer cells. The difference with published light microscopic data probably reflects the higher morphologic resolution and quantifiable immunoreactivity of the immunoelectron microscopy.