BRAF and melanoma: Yancovitz et al. used mutation-specific real-time polymerase chain reaction (RT-PCR) to examine intra- and inter-tumoral heterogeneity of the BRAF mutation.51 To determine intratumoral heterogeneity, laser microdissection of three to five sites from nine primary melanomas was performed and showed variability in the percentages of BRAF-mutant cells across the tumor sites.