Objectives: To explore whether the metabolic switches proceed or succeed the histological changes in precancerous lesions. To validate pyruvate kinase isoform 1 (PKM1) and pyruvate kinase isoform 2 (PKM2) as a histological biomarker to predict the progression of endometrial hyperplasia into invasive cancer status.
Methods: The records of 56 patients with a primary diagnosis of complex hyperplasia with atypia after endometrial biopsy were selected and analyzed retrospectively. A set of 3 consecutive sections at 4-μm thickness were cut and studied with immunohistochemical stains. From each case, 2 to 3 fields with a diagnosis of complex hyperplasia with atypia were selected and compared. A single pathologist blinded to the final diagnosis assigned the scoring.
Results: Positive immunostaining for PKM1 was observed in 31.25% (10 out of 32) of initial endometrial biopsy with the diagnosis of complex hyperplasia with atypia and final diagnosis of endometrial cancer, while 91.67% (out of 24) of patients with final diagnosis of negative endometrial cancer had endometrial biopsy with positive PKM1 staining ( P < .001). Positive immunostaining for PKM2 was observed in 100% of patient with endometrial biopsy result of endometrial hyperplasia with atypia (56 of 56).
Conclusions: Lack of staining with PKM1 expression may help to predict the fate of endometrial hyperplasia. The disappearance of this marker is associated with the progression of hyperplasia toward cancer phenotype. Further studies are needed to understand the causes and potential mechanisms for suppressing Pyruvate Kinase Isoform 1 expression in endometrial hyperplasia.
Keywords: PKM1; PKM2; endometrial cancer; immunostaining; pyruvate kinase; receiver operating characteristic curve; sensitivity; specificity.