Splenic, thymic, bony and lymph node metastases from orthotopic human lungcarcinomas in immunocompromised mice

In orthotopic animal models of human lung cancer, bone and lymph node metas tases have been observed with high frequency after periods of a few weeks, but metastases to other organs are rare. This study evaluated development o f distant metastases over a six-month period in a model of orthotopic lung carcinoma in immunocompromised mice. Human A549 lung adenocarcinoma cells w ere stably transfected to express high levels of green fluorescent protein. Suspensions of 1 x 10(6) cells were instilled into the lungs of athymic an d SCID mice to produce orthotopic human lung carcinomas.. All animals had p rimary tumors at termination of the experiment sh months later. Splenic met astases and lymph node metastases were present in 70% of the! animals and t wo of the three SCID mice had thymic metastases. Three animals had bony met astases. Thus, a high percentage of immunocompromised mice with orthotopic lung carcinomas ultimately develop metastases.