CLCA1 is Poorly Expressed in Stomach Adenocarcinoma and Correlates with Immune Infiltration

Abstract

Calcium-activated chloride channel regulator 1 (CLCA1) is associated with cancer progression. The expression and immunologic function of CLCA1 in stomach adenocarcinoma (STAD) remain unclear. In this investigation, the expression of CLCA1 in STAD tissues and its involvement in the progression and immune response of STAD were examined using databases such as cBioPortal, TISIDB, and UALCAN. In order to validate the expression level of CLCA1 protein in gastric adenocarcinoma, thirty clinical tissue specimens were gathered for immunohistochemical staining. The findings indicated a downregulation of CLCA1 in STAD patients, which was correlated with race, age, cancer grade, Helicobacter pylori infection, and molecular subtype. Through the examination of survival analysis, it was identified that diminished levels of CLCA1 within gastric cancer cases were linked to decreased periods of post-progression survival (PPS), overall survival (OS), and first progression (FP) (P<0.05). The CLCA1 mutation rate was lower in STAD, but the survival rate was higher in the variant group. The correlation between the expression level of CLCA1 and the levels of immune infiltrating cells in STAD, as well as the immune activating molecules, immunosuppressive molecules, MHC molecules, chemokines, and their receptor molecules, was observed. Gene enrichment analysis revealed that CLCA1 may be involved in STAD progression through systemic lupus erythematosus (SLE), proteasome, cell cycle, pancreatic secretion, and PPAR signaling pathways. In summary, CLCA1 is anticipated to function as a prognostic marker for patients with STAD and is linked to the immunization of STAD.