Transforming activity of nasopharyngeal carcinoma DNA detectable in mouse JB6 cells.

A JB6 mouse epidermal recipient cell line has been used to detect nasopharyngeal carcinoma (NPC) DNA-associated transforming activity that is not detectable in the NIH 3T3 focus assay. NPC DNA showed both transforming activity and activity for transferring sensitivity to tumor-promoter-induced neoplastic transformation, assayed in 2 different variants of mouse JB6 cells. Comparison of DNAs from various NPC sources that did or did not harbor EBV DNA and that varied in degree of differentiation showed similar transforming activities and similar activities for transferring promotion sensitivity. Thus both a NPC DNA-associated promotion sensitivity and an oncogenic activity function independently of concurrent EBV gene expression.