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. The gene discussed is PKM; the disease is breast carcinoma.