miRNA as a Prognostic Marker in Small Lung Cell Carcinoma

Small-cell lung carcinoma (SCLC) is one of the most aggressive and therapeutically challenging malignancies. It is characterised by rapid progression, early metastasis and frequent relapse. Despite considerable advances in molecular oncology, effective biomarkers for prognosis and treatment response remain elusive. In this review, we summarise and discuss recent evidence on microRNAs (miRNAs) as central regulators of SCLC biology and their potential clinical applications. A narrative review of the literature was conducted. Search of PubMed and Scopus databases identified 14 miRNAs, including miR-7-5p, miR-22-3p, miR-134, miR-181b, miR-200b, miR-335, miR-335-5p, miR-495, miR-24-3p, miR-30a-5p, miR-30a-3p, miR-100, miR-1 and miR-494, which are linked to tumour progression, therapy resistance and metastasis. These molecules influence several signalling cascades, including PI3K/Akt, Hippo, TGF-β, PARP1-mediated DNA repair and autophagy. Their abnormal expression correlates with patient outcome and may enable plasma- or exosome-based non-invasive monitoring. In particular, strategies that restore or inhibit miRNA activity using mimics or antagomiRs show promise in improving drug sensitivity and complementing current treatment options. Overall, emerging evidence supports the integration of miRNA profiling into precision oncology for SCLC, with the aim of refining diagnosis, risk assessment and therapeutic decision-making.