Tissue expression of Squamous Cellular Carcinoma Antigen (SCCA) is inversely correlated to tumor size in HCC

Abstract

Background: This study aimed to investigate squamous cellular carcinoma antigen (SCCA) in serum and in tumoral and paired peritumoral tissues. We studied 27 patients with liver cirrhosis (LC) and 55 with HCC: 20 with a single nodule < 3 cm (s-HCC) and 35 with a single nodule > 3 cm or multifocal (l-HCC).

Methods: Serum SCCA was measured by the ELISA kit, and in frozen tissues by immunohistochemistry, quantified with appropriate imaging analysis software and expressed in square microns. Continuous variables are reported as means and 95% confidence intervals. Comparisons between independent groups were performed with a generalized linear model and Tukey grouping. Pearson's correlation coefficients were determined to evaluate relations between markers. Qualitative variables were summarized as count and percentage. Statistical significance was set at p-value < 0.05.

Results: Serum SCCA values in LC patients were 0.41 (0.31-0.55) ng/ml and statistically different from both HCC groups: 1.6 (1.0-2.6) ng/ml in s-HCC, 2.2 (1.28-2.74) ng/ml in l-HCC. SCCA in hepatic tissue was 263.8 (176.6-394.01) microm2 in LC patients, statistically different from values in s-HCC: 1163.2 (863.6-1566.8) microm2 and l-HCC: 625.8 (534.5-732.6). All pairwise comparisons between groups yielded statistically significant differences. Tumoral SCCA resulted linearly related with nodule size, showing a statistically significant inverse relation between the two variables (b = -0.099, p = 0.024).

Conclusion: There was no statistically significant correlation between tissue and serum levels of SCCA. The significantly stronger expression of SCCA in smaller compared to larger HCC could be important for early HCC detection. However, the increased expression in peritumoral tissue could affect the significance of serological detection.

Figure 1

Tissue expression of SCCA. In Figure 1A, immunohistochemistry of SCCA in small and large HCC at low (A, C) and high (B, D) magnification. Paired peritumoral tissue at low magnification of small (E) and large (F) HCC. In A, C, E and F scale bar = 100 μm, in B and D scale bar = 50 μm. In Figure 1B, 95% Confidence intervals of neoplastic tissue SCCA in the different HCC patients groups.

Figure 2

95% Confidence intervals of non neoplastic peritumoral tissue SCCA in the different HCC patients groups.

Figure 3

95% Confidence intervals of serum SCCA in the different HCC patients groups.

Figure 4

Scatter plot of serum SCCA in tumoral and peritumoral tissue in HCC patients, and tissue SCCA in LC patients. Ln = natural logarithm.