Our findings provide strong circumstantial evidences to suggest that, despite the well-known histologic and molecular intra-tumor heterogeneity of lung malignancies, the expression of p16Ink4A is homogeneous across each individual neoplastic entity, allowing the analysis of a small area of the tumor, such as a core biopsy, as representative of p16Ink4A status of the entire lesion. The gene discussed is CDKN2A; the disease is neoplasm.