MKI67 and cancer: Similar to our findings with JPT1, recent assessments of MKI67 have identified that this hallmark biomarker of cellular proliferation does not directly contribute to tumor cell proliferation,26, 27 but rather functions to maintain cancer stem cell populations27 and facilitates chromosomal motility and mitotic spindle interactions.28 To gain further insight into the possible biologic roles of JPT1 in EC cells, we performed an immunoprecipitation‐mass spectrometry‐based analyses of JPT1 in sub‐confluent RL95‐2 cells to identify functional binding partner candidates.