Comment on ‘Testing patterns, patient and tumour characteristics and survival by NRAS and KIT genotype in melanoma’: can survival associations be inferred from selectively tested populations?

In this correspondence, we comment on the recent study by Mistry et al. examining *NRAS* and *KIT* testing patterns and survival in melanoma using a national English cohort. While acknowledging the important contribution of this large real-world dataset, we raise considerations regarding the interpretation of genotype–survival associations derived from selectively tested populations, where clinically driven molecular testing may introduce selection-related biases. We suggest that caution may be warranted when interpreting the apparent lack of prognostic association between *NRAS* mutation status and survival and emphasize the need for more systematically genotyped cohorts to clarify biological prognostic effects.