Loss of LIMCH1 predicts poor prognosis in patients with surgically resected Lung Adenocarcinoma: A study based on Immunohistochemical Analysis and Bioinformatics

Abstract

Background: LIMCH1, a novel actin-binding protein, is reported to correlate with tumorigenesis in multiple cancer types, but its clinical prognostic value in lung adenocarcinoma (LUAD) patients remains unclear. Methods: A total of 196 patients with LUAD who underwent R0 resection were included for analysis. We integrated immunohistochemistry (IHC) and data mining analyses to determine LIMCH1 expression in tumor specimens; the chi-square test was used to explore the correlation between clinicopathologic factors and LIMCH1 expression in LUAD; Kaplan-Meier curves and the Cox proportional hazards model were used to investigate the clinical prognostic role of LIMCH1 expression in patients with LUAD; and DAVID enrichment and gene set enrichment analysis (GSEA) were used to determine the underlying molecular mechanism. Results: LIMCH1 protein and mRNA expressions were significantly decreased in LUAD tissues. LIMCH1 mRNA expression was a potential diagnostic indicator in the TCGA cohort, and was associated with poor prognosis. IHC results in our LUAD cohort demonstrated that the LIMCH1 expression level was significantly associated with pleural invasion, tumor length, tumor differentiation grade, and clinical tumor stage. Patients with higher LIMCH1 expression had longer overall survival times. Cox multivariate survival analysis showed that LIMCH1 expression independently predicted the outcome. GO and KEGG clustering analyses showed that LIMCH1-related genes may be involved in 'cell adhesion', 'signal transduction', and several cancer-related pathways. GSEA showed 8 enriched hallmarks in the low LIMCH1 expression group, including mTOR signaling, MYC signaling, DNA repair, and G2M checkpoint. Conclusions: Our findings suggest that LIMCH1 may serve as a promising biomarker to predict LUAD prognosis.

Keywords: LIMCH1; TCGA; immunochemistry; lung adenocarcinoma; prognosis.

Figure 1

Flowchart of the enrollment process.

Figure 2

Aberrant LIMCH1 expression, prognostic value, and survival analysis in the TCGA-LUAD cohort. (A) Low expression of LIMCH1 in 57 paired of LUAD tissues. (B) LIMCH1 mRNA expression decreased in LUAD tissues than normal lung tissues. Diagnostic value (C) and survival analysis (D) of patients from the TCGA cohort.

Figure 3

The protein expression of LIMCH1 in LUAD tissues and non-tumor tissues. IHC staining of normal lung tissue (A) and LUAD tissue (B) from HPA datasets. Representative images of IHC staining of LIMCH1 in paired adjacent normal tissues (C) and LUAD tissues (D) (Magnification ×400). Tumor tissues without LIMCH1 staining which score=0 (E); weak staining of LIMCH1 which score=1 (F); moderate staining of LIMCH1 which score=2 (G); strong staining of LIMCH1 which score=3 (H); (Magnification ×400). Representative images of step percentages of LIMCH1 staining in 1%-25% which score=1 (I); LIMCH1 staining percentage of 26%-50% which score=2 (J); LIMCH1 staining percentage of 51%-75% which score=3 (K), LIMCH1 staining percentage of >75% which score=4 (L); (Magnification ×40). Bar scale: 50 µm.

Figure 4

Survival analysis of LUAD patients with different expressions of LIMCH1 based on IHC staining.

Figure 5

DAVID analysis of co-expressed genes. (A) the intersection of co-expressed genes between MEM and cBioPortal datasets. (B) KEGG analysis revealed significantly enriched pathways. GO terms of Biological Process (C) and Cellular Component (D).

Figure 6

Gene Set Enrichment Analysis of LIMCH1. (A-D) The most significantly associated pathways. (A) MTORC1 signaling; (B) MYC targets; (C) DNA repair; (D) G2M checkpoint; (E) Heat Map of the top 100 genes.