Tumor cells carried through autotransfusion. Are these cells still malignant?

A suspension of 3 X 10(7) cells of longterm carcinoma cell lines--HLaC 78 and 79 from human laryngeal carcinoma, CaKi 1 derived from renal cell carcinoma and PC 3 from prostatic carcinoma,--was pumped with maximum pressure up to 5 times through the filters of the Bentley autotransfusion device. Following filter passage after centrifugation the untrapped cells were recovered, counted and brought in culture under appropriate conditions. As soon as monolayers were obtained 3 X 10(6) cells were transferred subcutaneously into athymic mice. The time intervals of growth in culture and of developing tumor nodules in nude mice were measured. The histological pattern of the daughter tumors in nude mice was compared with the genuine tumor. After the first filter passage 12.3% respectively 18.2% untrapped cells were found. This number dropped to 3% after the 5th passage. After the 5th passage in only 3 out of 5 experiments there were enough cells to start a culture. After the first passage cell proliferation in the culture as well as yielding tumor nodules in nude mice was markedly reduced. HLaC78 died. After the 5th passage cell growth in the culture as well as tumor growth in nude mice was reduced the more while using HLaC79. Taking CaKi 1 and PC 3 both parameters showed identical growth behaviour as compared with the original not-filter-passaged cells. The histological findings were identical with the pattern of the genuine tumors.