PKM and neoplasm: For example, using the prediagnostic breast cancer plasma samples collected as a part of the Women’s Health Initiative (WHI) observational study, Ladd et al. [27] demonstrated that the circulating levels of PKM2, the oncogenic isoform of the pyruvate kinase, the key mediator of the Warburg effect in malignant tumors [28], and a well-established tumor marker Tumor M2-PK [29,30,31,32], are particularly high in the blood plasma samples collected within the 150 days prior to the diagnosis of the breast carcinoma, but not in samples collected further from diagnosis.