Morphological, biological, and biochemical characteristics of a benign human trichilemmoma cell line in vivo and in vitro.

A cell line of a benign tumor, trichilemmoma, was established in vitro and has been maintained in culture for 1.5 years with more than 30 passages. Plating efficiency was less than 0.1%, and population doubling time was 10 days. Saturation density was 10(5) cells/sq cm at the time of a monolayer with 98% cell viability. Ultrastructurally, tissue-cultured trichilemmoma cells showed desmosome-tonofilament complexes at cell-to-cell junctions. The tissue-cultured cells synthesized abundant glycogen (50 to 100 microgram/10(6) cells) e was 10 days. Saturation density was 10(5) cells/sq cm at the time of a monolayer with 98% cell viability. Ultrastructurally, tissue-cultured trichilemmoma cells showed desmosome-tonofilament complexes at cell-to-cell junctions. The tissue-cultured cells synthesized abundant glycogen (50 to 100 microgram/10(6) cells) e was 10 days. Saturation density was 10(5) cells/sq cm at the time of a monolayer with 98% cell viability. Ultrastructurally, tissue-cultured trichilemmoma cells showed desmosome-tonofilament complexes at cell-to-cell junctions. The tissue-cultured cells synthesized abundant glycogen (50 to 100 microgram/10(6) cells) as observed in vivo. Gas chromatographic analysis revealed that extracted glycogen was composed of glucose alone. Chromosome analyses with trypsin-Giemsa banding showed an abnormal karyotype with hypodiploid modal numbers of 44 and 45. There were four marker chromosomes observed in 100% of cells in 100 metaphase cells examined. Cells did not grow on fibroblast monolayers or in soft agar in vitro but did induce tumors in athymic nude mice (12 of 15) after the s.c. injection of tissue-cultured cells (2.5 x 10(6) to 4.5 x 10(7) cells/mouse). The histological characteristics of the tumors in nude mice were similar to those of the original tumor. This is the first time, to our knowledge, that a benign human tumor cell line has been established in vitro which can induce tumors in nude mice.