CD4 and neoplasm: There was no significant difference in CD4/CD8 ratios between healthy non-bearing male C57BL/6 mice and the tumor-bearing female BALB/c mice (described below) (P=0.589, n=6 each); however, it is not possible to determine from these studies whether the absence of difference between male and female mice is an effect of sex, strain, or tumor bearing status of the mice (Figure 2A).