The alteration of MHC class I expression in cervical cancer

ABSTRACT

It was well established that HPV infection, especially type 16 and 18 is the major cause of cervical cancer. Immune evasion of infected cells or tumor cells is also known as one of contributing factors of tumor development caused by down-regulation of MHC class I expression. The aim of this study is to investigate the level and pattern of MHC class I expression in 182 cervical cancerous tissues and 57 normal cervix using immunoperoxidase staining technique. Of 182 cervical cancerous tissues, 50 cases were classified as pre-cancerous lesions whereas, 132 cases were invasive cervical carcinoma. No significant association in grading or intensity of MHC class I was shown between patient and control group. Interestingly, the distribution pattern of MHC class I was significantly shown as non-surface presenting molecules accumulating in cytoplasm of cancerous tissues compared to normal cervix tissues with p-value \< 0.001 χ² test .This result indicates that tumor cells have lost their immune surveillance by reducing their antigen presenting MHC class I molecules at cell surface. Moreover, this alteration can be used as an early marker for cancer prognosis in pre-cancerous group. Therefore, the mechanism of the impairment in antigen presenting of MHC class I molecules should be investigated in further study.