CIRCULATING TUMOUR ASSOCIATED ANTIGENS AS AID TO EARLY DIAGNOSIS OF CARCINOMA OF CERVIX

Abstract

Earlier studies by this author in 1976 provides evidence of an association between an infective, sexually transmitted agent, the Herpes Simplex Virus Type-2 (HSV-2) and human carcinoma of the cervix, irrespective of geographic location or ethnic origin of the individuals. Similarly, HSV-2 related antigens were demonstrated by the indirect immuno-fluorescent technique in desquamated cells of carcinoma of the cervix tissues from tumour bearing patients. To highlight the potentials of the detection of tumour antigens in tumour-bearing patients as aid to early diagnosis of the cancer, isolation and purification of the Tumour Associated Antigens (TAA) of human cancer of the cervix were attempted by immunological and physiological procedures in this study. The antigens preparations, one of the Soluble Antigens (SA), and the other, the Membrane bound Antigens (MBA) were prepared from a pool of cancer of the cervix (CaCx) tissues. The soluble antigens were extracted by homogenization in Earle's Balanced Salt Solution (EBSS) containing antiboitics, and the membrane-bound antigens were solublised by 3-molar potassium chloride (3 Molar KCl). For isolation and purification of TAA, procedures for the purification of proteins were explored. These include physico-chemical stepwise ammonium sulphate fractionation, sephadex ion exchange chromatography, sephacryl-5-200 gel filtration, and affinity chromatography to eliminate the normal tissue components of the antigens fractions. Hyperimmune rabbit sera were then prepared against the partially purified TAA. Sensitivity of the test method was low, the specificity was high, and could provide a means of early diagnosis of neoplastic changes in the cervix. The detection of Circulating-TAA as tumour markers in sera of patients, may some day become routine, and thus make earlier diagnosis of cancer possible. Indications are that immune-diagnostic procedures can be designed in ways that are reproducible, simple and reliable. Such serological tests would extend our present ability for detection and monitoring of malignancies.