ALCAM (CD166) expression and serum levels in pancreatic cancer

Abstract

Background: This study was conducted to evaluate the expression of the activated leukocyte cell adhesion molecule (ALCAM) in pancreatic cancer (PAC) and to determine whether or not the ectodomain shedding of ALCAM (s-ALCAM) could serve as a biomarker in the peripheral blood of PAC patients.

Material and methods: Tissue specimens and blood sera of patients with PAC (n = 264 and n = 116, respectively) and the sera of 115 patients with chronic pancreatitis (CP) were analyzed via ALCAM immunohistochemistry and s-ALCAM ELISA tests. Results were correlated with clinical, histopathological, and patient survival data (Chi-square test, Kaplan-Meier analysis, log-rank test, respectively).

Results: ALCAM was expressed in the majority of PAC lesions. Immunohistochemistry and serum ELISA tests revealed no association between ALCAM expression in primary tumors or s-ALCAM and clinical or histopathological data. Neither ALCAM nor s-ALCAM showed a significant impact regarding overall survival (p = 0.261 and p = 0.660, respectively). S-ALCAM serum levels were significantly elevated compared to the sera of CP patients (p<0.001). The sensitivity of s-ALCAM in detecting PAC was 58.6% at a specificity of 73.9% (AUC = 0.69).

Conclusions: ALCAM is expressed in the majority of PAC lesions, but statistical analysis revealed no association with clinical or pathological data. Although significantly elevated in patients with PAC, the sensitivity and specificity of the s-ALCAM serum quantification test was low. Therefore, its potential as a novel diagnostic marker for PAC remains elusive and further investigations are required.

Figure 1. Representative immunohistochemical ALCAM stains of primary pancreatic cancer (PAC) lesions.

(A) and (B) strong ALCAM expression, (C) and (D) medium and (E) no expression. (F) Healthy pancreatic tissue. (G) Complete scan of the PAC tissue microarray.

Figure 2. Kaplan-Meier overall survival analysis.

(A) Immunohistochemical ALCAM staining of primary pancreatic cancer specimens and (B) low and high s-ALCAM serum levels (patients who died during the first 30 days after surgery were excluded).

Figure 3. S-ALCAM serum analysis.

(A) s-ALCAM serum levels of the patients with pancreatic cancer (PAC) and chronic pancreatitis (CP) and healthy control blood donors (p<0.001). (B) Receiver operating characteristic (ROC) curves of s-ALCAM for the diagnosis of PAC versus CP patients.