Cervical lymph node metastasis: model for study of head/neck melanoma.
Tumour cells spread from primary tumours to form distant metastatic deposits by both lymphatic and blood routes. Melanomas occurring in the head and neck have an extremely poor prognosis largely in part due to late detection resulting in extensive dissemination by lymphatic metastasis. The purpose of this study was to develop an animal model for the study of head and neck melanoma metastasis. B16-F1 parental cells were injected into the subcutis of the ear mid-lobule of C57BL/6 mice. At selected time periods after inoculation, animals were killed by cervical dislocation and autopsied. In some animals tumours had spread to the cervical lymph nodes. Examination of organ systems revealed no evidence of distant metastases. Histological examination of the cervical lymph nodes revealed tumour invasion, beginning at a subcapsular sinus and progressing into the paracortical sinuses. Cells from these nodes were adapted to cell culture, expanded by passage and reinjected into new mice. Subsequent generations of lymph node-selected B16 cell lines were more metastatic than their parental cell line, as evidenced by a more rapid appearance of cervical lymph node and extensive node invasion. Morphologically, the lymph node-selected B16 cell lines were more dendritic than the original B16-F1 parent line and had a larger number of pseudopodial projections. Perhaps increased expression of pseudopods by the metastatic variants may allow for greater migratory potential and hence increased metastatic ability. These results indicate that highly mobile variant B16 sublines can be selected with an increased capacity for cervical lymphatic metastasis.
Barkhordar
R A
RA
Department of Restorative Dentistry, University of California, San Francisco, USA.
Berston
E D
ED
Ramos
D M
DM
D000818:Animals; D008207:Lymphatic Metastasis; D008546:Melanoma, Experimental / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009333:Neck; D014407:Tumor Cells, Cultured