The basaloid nests showed a p27kip1 positivity that, when present, was specifically polarized and located in the cells toward the central necrosis, some of which with a squamous-like appearance, whilst the cells at the invading front of the tumour, showing peripheral nuclear palisading arrangements, were negative for p27kip1 and intensely positive for p53, and Ki67/Mib-1. This evidence concerns the gene CDKN1B and neoplasm.