Immunohistochemistry analysis of pancreatic tissue revealed significant differences in the number of CD20+ B cells, as shown on Figures 3A, B (group 5 vs 1 p=0.009; group 5 vs 3 p=0.03; group 6 vs 1 p=0.03), CD3+ T cells (group 5 vs 1 p=0.003; group 5 vs 3 p=0.03; group 6 vs 1 p=0.006; 6 vs 3 p=0.045), CD4+ T cells (group 5 vs 1 p=0.005; group 6 vs 1 p=0.01), and CD8+ T cells (group 5 vs 1 p=0.003; group 6 vs 1 p=0.004) in the pancreas of K-Ras mutant mice with developed PC or PanIN (groups 5 and 6) compared to control mice (groups 1 and 2). This evidence concerns the gene KRAS and pachyonychia congenita.