ACTA1 and melanoma: To systematically investigate the prognostic significance of various types of blood vessels according to pericyte coverage and vessel sprouting/stability using unbiased computer imaging methods in craniotomy melanoma specimens, we measured total (CD31+, single-color IHC, n=43), mature (CD31+αSMA+, two-color IF, n=41), immature (CD31+αSMA-, two-color IF, n=41), stable/non-sprouting (CD31+Ang2+, two-color IF, n=29), and unstable/sprouting (CD31+/Ang2-, two-color IF, n=31) blood vessel density within the melanoma compartment.