Assessment of Transthyretin and Key Biomarkers for Lung Cancer Diagnosis

Background: Lung cancer (LC) is one of the leading causes of cancer-related mortality worldwide, with poor prognosis in advanced stages. Early detection through reliable biomarkers is essential for improving survival rates. Transthyretin (TTR), a transport protein for thyroid hormones, has been suggested as a potential diagnostic marker, but its clinical utility in LC remains underexplored. Purpose: This study aimed to evaluate the diagnostic potential of serum TTR in combination with thyroid hormones and other biochemical markers in LC patients, and to determine which parameters provide the highest sensitivity and specificity for early diagnosis. Methods: A case-control study was conducted on 60 participants (30 LC patients—19 with NSCLC and 11 with SCLC—and 30 healthy controls). Serum levels of TTR, T3, T4, TSH, Albumin, HDL, Triglycerides (TG), Cholesterol, and Total Protein were measured using ELISA and standard biochemical assays. Data were analyzed using ANOVA, Mann–Whitney U test, Spearman/Pearson correlation, and ROC curve analysis to assess diagnostic performance. Results: LC patients showed significantly lower TTR, T3, TSH, Albumin, and Total Protein levels, and higher T4, HDL, TG, and Cholesterol levels compared to controls (p < 0.05). TTR and T4 demonstrated the strongest diagnostic performance, with AUC values of 0.831 and 0.922, respectively; T4 achieved 100% specificity. TTR correlated positively with Albumin, HDL, BMI, and TSH, and inversely with T4 and age. Conclusions: TTR and T4 are promising biomarkers for distinguishing LC patients from healthy individuals. Incorporating these markers into diagnostic panels may enhance early detection and improve clinical outcomes. Further research is warranted to validate these findings in larger, diverse populations.