Association of α-SMA/FAP-positive cancer-associated fibroblasts with clinicopathological features and prognosis in extrahepatic cholangiocarcinoma.

Objective: This study aimed to evaluate the value of cancer-associated fibroblasts (CAFs) that positively express α-smooth muscle actin (α-SMA) and fibroblast activation protein (FAP) as survival indicators for patients with extrahepatic cholangiocarcinoma (eCCA).

Methods: The clinicopathological data of eCCA patients who underwent surgical treatment in Tianjin Nankai Hospital from January 1, 2019, to December 31, 2022, were retrospectively analysed. A total of 79 patients were included, 49 were male and 30 were female, with an age of (64.3 ± 8.3) years. Clinicopathological data such as age, gender, tumour location, lymph node metastasis, tumour differentiation degree, and TNM stage of the patients were recorded. The expressions of α-SMA and FAP, the markers of CAFs, in eCCA were detected by immunohistochemistry. The relationships between the expressions of the two proteins and the clinicopathological data and prognosis of the patients were analysed.

Results: The positive expressions of α-SMA and FAP in CAFs were observed in 78.5% (62/79) and 35.4% (28/79) of the patients, respectively. There was a highly positive correlation between the expression of α-SMA and that of FAP (r = 0.992, P < 0.001). Univariate analysis showed that CAFs with positive FAP expression and tumour location were statistically significant in terms of overall survival time and recurrence-free survival time. Multivariate analysis indicated that positive FAP expression and tumour location might be independent factors affecting overall survival time and recurrence-free survival time.

Conclusions: CAFs with positive FAP expression may be a prognostic indicator of poor postoperative survival in eCCA patients and may serve as an independent predictor of poor postoperative survival rate in these patients.