To investigate whether the presence of tumors influences MC density in the skin, we identified MCs by histochemistry with staining for the MC marker tryptase (TPSAB1) and compared cell numbers in lesions of melanoma (n = 14) with the ones in slow-growing, non-metastatic basal cell carcinoma (BCC) (n = 6) and healthy skin (n = 8). Here, TPSAB1 is linked to skin basal cell carcinoma.