MKI67 and neoplasm: From reviewing and analyzing previous studies to our findings, serum exosomal miR-590-5p indicated a better sensitivity and specificity than serum tumor biomarkers which had reportedly low specificities and sensitivities (Schneider and Schulze, 2003; Yang et al., 2016); in addition, we were surprised to observe a negative correlation of exosomal miR-590-5p levels with increased ki-67 protein levels which is recognized to reflect the proliferation of tumor cells.