Table 4. Intra-individual correlations: in vitro senescence markers versus in situ p16INK4a positive human fibroblasts (3B).

	Coefficient	P-value
Non-stressed
p16INK4a	0.064	0.655
TAF	-0.030	0.835
ROS	-0.097	0.498
SAβ-gal	-0.042	0.772
Stressed
p16INK4a	0.091	0.527
TAF	0.014	0.922
ROS	-0.095	0.506
SAβ-gal	0.023	0.871

Values are depicted as Pearson's partial correlation coefficient, adjusted for batch. Data for in situ and in vitro senescence markers were available for N=52 donors. P16INK4a positive dermal fibroblasts: number of positive cells per 1mm2 dermis. All in vitro variables are the mean of short-term experiments. P16INK4a: % of p16 positive cells; ROS: mean fluorescence intensity peak; SAβ-gal: median fluorescence intensity peak; telomere-associated foci (TAF): % of nuclei with ≥1 53BP1 foci per nucleus, coinciding with telomeric DNA.