FURTHER STUDY ON THE INFLUENCE OF PRIMIPAROUS AGE AND LITTER NUMBER ON THE MAMMARY TUMOR AGE IN MICE
1968 Volume 59 Issue 3 Pages 217-222
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1968 Volume 59 Issue 3 Pages 217-222
Succeeding to the previous report, it was confirmed that the primiparous age (the virginal period) as well as the litter number played some significant rôle in determining the spontaneous mammary tumor age of mice.
The relative importances of the primiparous age, litter number, and the rest factors in determining the tumor age were 27.4, 45.8, and 26.8%, respectively, in C3H/He mice and 17.2, 43.8, and 39.1%, respectively, in Swiss albino mice, indicating that the tumor age is much dependent upon both the primiparous age and the litter number at least in the groups of mice used in the present experiment.
The equation for calculating the corrected tumor age was devised by subtracting the components of variance due to the individual differences in the primiparous age and the litter number from the tumor age.
Both the simple and rank correlations between the tumor age and the corrected tumor age obtained by this equation were found to be highly significant in both groups of mice. The significance of these findings is discussed.
