We included studies published within the last five years to avoid excessive variation in the detection methods between studies as p16 positivity previously ranged considerably and a large part of studies used a minimum of 5–69% staining [49] before ASCO published guidelines for defining a tumours as p16+ by a cut-off of 70% nuclear and cytoplasmic staining [15]. The gene discussed is CDKN2A; the disease is neoplasm.