Genes such as, PCNA, CKS1B, TPX2, UBE2C, CDC6, confirmed by the statistically significant analysis of microarray data, SAM, were among the positive proliferation genes differentially expressed by immortal cell lines, and matched tumor tissue/cell culture samples (Figure 1E, also see Table S2 – http://genome-www.stanford.edu/breast_cancer/PTCC/, for full list). The gene discussed is CKS1B; the disease is neoplasm.