To assess the tumorigenicity of
D4M melanoma cells, we intradermally
injected a range (300–300 000)
of cells into B6 and NSG host mice.
Each concentration of cells was
injected into four B6 and four NSG
mice. Of the eight mice injected with
300 cells, no tumors developed in
any of the mice after 27 weeks. In
contrast, it took only two weeks for
tumors to be observed in mice that
received ≥3000 cells, and only
one week for tumors to be observed
in mice that received 300 000 cells
(Table 1). Tumors arose with similar
kinetics in B6 and NSG host mice;
there was no significant difference in
the average tumor size between NSG
and B6 mice injected with 3000