Fig 4.

Tumor formation in skin of K5.COX-2/667^+/− transgenic mice after DMBA initiation alone. Tumor incidence (a) and yield (b) after DMBA initiation alone of wt (○) and K5.COX-2/667^+/− transgenic mice (•). Epidermal PG levels (c, mean ± SEM; PGE₂, black bars; PGF_2α, white bars; 6-keto-PGF_1α, gray bars; 15-deoxy^Δ12,14-PGJ₂, Inset) are shown for tumor-bearing K5.COX-2/667^+/− transgenic (667, n = 3) and age-matched tumor-free wt (n = 5) mice; P values for PGE₂, PGF_2α, and 15-deoxy^Δ12,14-PGJ₂ were 0.036. Representative hematoxylin/eosin-stained sections are shown for sebaceous gland adenoma (d and e), papilloma (f and g), and squamous cell carcinoma (h and i) derived from K5.COX-2/667^+/− transgenics. [Magnification: d, f, and h, ×50; e and i, ×160; g, Inset, ×400.]