Letter: Micro-RNA-125b and its use as a biomarker of systemic malignancies besides urothelial cancers

I read with great interest the recent article by Snowdon and colleagues.¹ MiR-125b may serve as a biomarker in a number of systemic malignancies besides urothelial cancers.

For instance, in non- small cell lung carcinomas (NSCLC) miR-125b expression is a significant biomarker. In fact, miR-125b expression in these malignancies is an independent determining factor of prognosis. Patients with NSCLC and high miR-125b levels typically exhibit a poor clinical outcome.² Lower levels of miR-125b are seen in those with well differentiated tumours in comparison to those with poorly differentiated tumours. Patients with lung malignancies that do not respond to therapy typically exhibit higher levels.

Similarly, miR-125b influences clinical prognosis in colorectal malignancies. Progression of the primary tumour involves a direct involvement of miR-125b. miR-125b acts by attenuating p53 expression in the malignant cells.³ Colorectal carcinoma patients with high miR-125b levels typically have a poor clinical outcome in contrast to patients who express low levels of miR-125b. Individuals with high miR-125b expression develop larger tumours that exhibit greater invasiveness. These findings have been confirmed by Nishida and colleagues in a recent study.⁴

The above examples clearly illustrate the significance of assessing miR-125b levels in determining the prognosis in a number of systemic malignancies. There is a clear need for further studies to further explore the possible relationship of miR-125b with clinical prognosis in other systemic malignancies.