We investigated the biological and histopathological characteristics of seven human tumour cell lines established from primary tongue squamous cell carcinoma (OSC-1), from metastasised lymph nodes of the gingival carcinoma (OSC-2 and OSC-3) and from tongue carcinoma (remaining four lines). The doubling time ranged from 22 h (OSC-2 and OSC-4) to 55 h (OSC-7), and did not correlate with tumour cell stratification in a collagen gel matrix. An invasive tendency was most prominent in OSC-2 and OSC-4; with the other cell lines, except OSC-6 and OSC-7, only a few sporadic invading cells were found in the tissue culture. In the cell lines established from the metastatised tumours, originally exhibiting grade 3 invasion, the invasion became more sporadic when the tumour cells were xenografted into the tongues of nude mice, while an invasion similar to the original was observed in the cell lines obtained from the original site (OSC-1) and from tumours of Grade 4C invasion. These findings suggest that the biological behaviour of the established tumour cells is markedly different even in tumours of the same tissue origin, and strongly invasive cells may selectively invade, and metastatise to the lymph nodes.