How early does microRNA overexpression occur before symptoms appear?

MicroRNA dysregulation is an early molecular event in carcinogenesis — it occurs at or near the time of initial malignant transformation, long before a tumor grows large enough to cause symptoms or to be detected by imaging. Research shows that miRNA overexpression is detectable during Stage I and Stage II disease, when tumors are typically smaller than 2 cm and have not yet spread to lymph nodes or distant organs. The clinical validation studies used by Yenos enrolled newly diagnosed Stage I and II cancer patients, confirming that the miRNA signal is present at these early stages. This is precisely why early detection through miRNA testing offers such a large survival advantage compared to symptom-based diagnosis.