Fascin-1 expression in non-small cell lung cancer and its diagnostic implications

Currently, a systematic explanation of the clinical application and diagnostic value of Fascin-1 (FSCN1) in lung cancer has not been established. This study used immunohistochemistry (IHC) to detect the expression level of FSCN1 protein in 276 cases of non-small cell lung cancer (NSCLC) tissues, to explore the clinical value of FSCN1 and its diagnostic value in distinguishing between lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). FSCN1 expression was analyzed in normal lung tissues, LUAD, and LUSC. The positivity rates were 0.0% (0/41) in normal tissues, 50.9% (85/167) in LUAD, and 98.2% (107/109) in LUSC. Furthermore, strong positivity was observed in 0.0% (0/41), 19.8% (33/167), and 93.6% (102/109) of these tissue groups, respectively. Both the overall positivity and the strong positivity rates of FSCN1 were significantly higher in LUSC than in either LUAD or normal lung tissues. ROC curve analysis demonstrated that FSCN1 positivity and strong positivity effectively discriminated LUSC, with areas under the curve (AUC) of 0.736 (95% CI: 0.679-0.794; P < 0.001) and 0.869 (95% CI: 0.824-0.914; P < 0.001), respectively. In LUAD, FSCN1 positive expression was significantly associated with male gender, tumor size >3 cm, poor differentiation, lymph node metastasis, and higher tumor stage. Similarly, FSCN1 strong positive expression was associated with male gender, tumor size >3 cm, poor differentiation, and smoking history. Multiple logistic regression analysis identified that independent predictors of FSCN1 positive expression in LUAD included poorly differentiated tumors (OR = 2.576; 95% CI: 1.085-6.114; P = 0.032) and higher tumor stage (OR = 2.316; 95% CI: 1.205-4.453; P = 0.012). Meanwhile, independent predictors of FSCN1 strong positive expression included male gender (OR = 3.036; 95% CI: 1.376-6.700; P = 0.006). Survival analysis revealed that FSCN1 positivity was significantly associated with reduced 5-year relapse-free survival (RFS) in LUAD patients (P = 0.025), though no significant association was observed with overall survival (OS). These findings indicate that FSCN1 may play an important role in lung cancer pathogenesis and progression, and could serve as a differential diagnostic marker between LUSC and LUAD.