CCND1 and melanoma: Immunostaining results showed significant upregulated expression of cyclin D1 in B16F10; bcat/Fb tumors (Fig. 5H) as compared with B16F10; Fb tumors (Fig. 5G), suggesting that there was an accelerated G1 to S phase cell cycle progression in B16F10; bcat/Fb melanoma tumors when stromal fibroblasts were deactivated through β‐catenin ablation.