Despite its rarity in this cohort, expression carried prognostic weight. Kaplan–Meier analysis showed significantly worse overall survival among patients with moderate or strong Claudin-18 staining compared with those whose tumors were negative or weak (log-rank p = 0.024). Mean overall survival was 121.0 months in the negative/weak group versus 76.6 months in the expressing group.

Event-free survival told a similar story. Patients with moderate or strong expression had significantly shorter event-free survival (log-rank p = 0.022), with mean event-free survival of 93.1 months in the negative/weak group versus 31.1 months among expressers. Progression-free survival showed a trend in the same direction, with poorer outcomes among patients with higher Claudin-18 expression, but the difference did not reach statistical significance (log-rank p = 0.066).

Notably, Claudin-18 expression did not correlate with any standard clinicopathological feature. The analysis found no significant associations with age, sex, tumor site, T stage, lymph node status, distant metastasis, TNM stage, histological subtype, or lymphovascular invasion (all p > 0.05). The picture became more complicated in multivariable modeling.

A binary logistic regression model including gender, age, lymphovascular invasion, tumor laterality, TNM stage, MSI status, histological type, and Claudin-18 expression was statistically significant overall (χ2(7) = 22.657, p = 0.002), yet none of the individual variables was independently associated with the outcome (all p > 0.05). Claudin-18 expression itself was not a significant predictor in the adjusted model (p = 0.931; odds ratio 0.63). The authors conclude that, although Claudin-18 expression was associated with poorer overall survival in this cohort, its independent prognostic value was not established.

Subject of Research: Claudin-18 expression and its prognostic significance in colorectal cancer

Article Title: Claudin-18 expression is associated with poorer overall survival in colorectal cancer

Article References: Al-Kabariti, A. Y., Abbas, M. A., Alashhab, M., Smarakan, S., & Sughayer, M. A. (2026). Claudin-18 expression is associated with poorer overall survival in colorectal cancer. PLOS One, 21(10), e0360740. https://doi.org/10.1371/journal.pone.0360740

Image Credits: AI Generated

DOI: 10.1371/journal.pone.0360740

Keywords: Claudin-18, colorectal cancer, immunohistochemistry, overall survival, event-free survival, prognosis, tight junction protein, retrospective study, biomarker, gastrointestinal cancer, expression, associated