Background: Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related deaths globally, accounting for approximately 85% of lung cancers. Although the level of diagnosis and treatment continues to improve, the patient’s prognosis is still unsatisfactory due to the high recurrence and metastasis rates. Searching for potential molecular markers is of great significance for early diagnosis, prognostic assessment and targeted treatment. Human aldehyde dehydrogenase 18 family member A1 (ALDH18A1) has been found to be associated with tumor proliferation and prognosis in a variety of cancers, but its expression and clinical significance in NSCLC are unclear. Aim: To verify the protein expression characteristics of NSCLC through immunohistochemical experiments on tissue chip, and provide theoretical basis for molecular diagnosis and targeted treatment of NSCLC. Materials and Methods: In this study, ALDH18A1 protein expression was determined in 80 cases of lung squamous cell carcinoma (LUSC), 52 cases of adenocarcinoma (LUAD), and adjacent tissues of combined tumors using TMA and IHC methods. Indirect IHC staining was performed on 4-μm-thick sections, and semiquantitative evaluation was performed based on the staining intensity and percentage of positive cells. ALDH18A1 expression was analyzed in relation to clinicopathological parameters (age, sex, TNM stage, clinical grade) and patient survival. Result: ALDH18A1 was highly expressed in the tumor tissues of 132 cases of LBCL, but was low or absent in the surrounding normal tissues. In LUSC, high ALDH18A1 expression was significantly associated with poor tissue differentiation (P<0.001), advanced TNM stage (P<0.001), distant metastasis (P=0.0327) and tumor size (P=0.0166). In LUAD, it was associated with poor tissue differentiation (P<0.001), advanced TNM stage (P<0.001) and tumor size (P=0.00302). According to Kaplan–Meier analysis, OS of patients with high ALDH18A1 expression was significantly shorter than that of those with low expression (LUSC: P=0.0014, LUAD: P<0.0001). The results showed that high ALDH18A1 expression was strongly associated with the infectivity of HLH and poor prognosis. Conclusion ALDH18A1 is highly expressed in NSCLC tissue and is related to tumor progression. It may serve as a potential molecular marker and treatment target, providing reference for the diagnosis and prognosis of NSCLC.

Background: Non-small cell lung cancer (NSCLC) is the most common pathological type of lung cancer, and its incidence and mortality rates have long ranked among the highest of malignant tumors worldwide. Through bioinformatics analysis, this study identified the oncogene ALDH18A1, which is closely related to the development of NSCLC. Recent studies have shown that ALDH18A1 is highly expressed in various malignant tumors and participates in regulating biological processes such as cell viability and proliferation. However, its specific role and molecular mechanism in NSCLC remain unclear. Aim: To investigate the expression characteristics of ALDH18A1 in NSCLC cells and its effects on cell viability and proliferation. Materials and Methods: The expression levels of ALDH18A1 in various NSCLC cell lines and normal lung cells were detected by real-time quantitative PCR (qPCR) and Western blot. NSCLC cell lines with high ALDH18A1 expression were selected, and ALDH18A1 was knocked down using siRNA technology. The effects of ALDH18A1 downregulation on cell viability and proliferation were evaluated using CCK-8 assays and colony formation assays, and the experimental results were analyzed using statistical methods. Result: The expression level of ALDH18A1 in NSCLC cell lines was significantly higher than that in normal lung cells, and the expression was particularly significant in H1975 cells. Knockdown of ALDH18A1 expression significantly reduced the viability and proliferation capacity of NSCLC cells, and the difference was statistically significant (P<0.05). Conclusion ALDH18A1 is highly expressed in NSCLC cells, and its downregulation can significantly inhibit the viability and proliferation of tumor cells, suggesting that ALDH18A1 plays a pro-tumor role in the occurrence and development of NSCLC and has research value as a potential oncogene and therapeutic target.