For example, the smaller cell cluster B4b was a highly proliferative tumor with cells at either the G2/M, or S phase (Fig. 2a, right two panels) and displayed high expression of MKI67, CDK4, and other proliferative markers such as PCNA, TK1, and TYMS (Supplementary Fig. 5a). The gene discussed is PCNA; the disease is neoplasm.