Association of miR-199a-3p and CDK7 expression with clinicopathological features of breast cancer.

BACKGROUND

Breast cancer (BC) remains the most common malignancy among women worldwide. miR-199a-3p has been implicated in several cancers, while Cyclin-Dependent Kinase 7 (CDK7) plays a critical role in cell cycle regulation and transcriptional control.

OBJECTIVE

To evaluate the expression profile and diagnostic performance of miR-199a-3p and CDK7 in BC tissues and investigate their associations with clinicopathological characteristics.

METHODS

This study was conducted on 30 paired BC and adjacent normal breast tissue samples collected in Erbil, Iraq. Expression levels of miR-199a-3p and CDK7 were quantified using qRT-PCR. Also, blood samples were collected to estimate CA 15 - 3.

RESULTS

Among 30 BC patients, there was a significant difference in miR-199a-3p expression in tumor tissues compared to paired control tissues (P = 0.0029), with a downregulation of 0.506-fold relative to the control group. In contrast, CDK7 expression did not differ significantly between tumor and control tissues (P = 0.140). The serum CA 15 - 3 levels were considerably higher in BC patients (P < 0.001) and the AUC was 0.754 (95% CI: 0.623-0.867) with a sensitivity of 43.3% and specificity of 96.7% at a threshold value of 25.1 U/mL. miR-199a-3p presented an AUC of 0.720 (95% CI, 0.581-0.839) and CDK7 an AUC of 0.621 (95% CI, 0.467-0.764). The combined miR-199a-3p/CDK7 model showed an AUC of 0.750 (95% CI: 0.619-0.886) with 76.7% sensitivity and 80.0% specificity. The higher CDK7 expression was associated with PR-negative status (P = 0.038).

CONCLUSION

miR-199a-3p may be a possible biomarker for BC diagnosis with considerably low expression and moderate diagnostic efficacy. The combination miR-199a-3p/CDK7 model enhanced diagnostic discrimination, while serum CA 15 - 3 showed good specificity. The relationship of CDK7 with PR status further supports its therapeutic importance.