Abstract 571: Comparative immunohistochemical study of basaloid and usual squamous cell carcinoma of the esophagus

Abstract

Abstract Basaloid squamous cell carcinoma (BSCC) is a rare epithelial malignancy variant of the typical SCC, and it has been associated to an aggressive behavior, with a high capacity for developing metastasis and low survival rates. It has been reported that less than 12% of the primary esophageal carcinoma have been diagnosed as BSCC. The study aimed to compare the protein expression of HER-2, EGFR, Ki-67, Cyclins A, B1 and D1 between usual SCC and BSCC. Immunohistochemistry of 94 usual ESCC and 17 EBSCC cases were carried out using Tissue Microarray technique. Immunohistochemical analysis of cyclins and growth factors receptors was based on frequency and intensity of tumor cells in each sample; Ki-67 analysis was based on the frequency of tumor cells showing strong nuclear positive staining. When the clinicopathological data were compared, only histological grade (p=0.000) showed a significant difference between the usual and basaloid SCC groups. No significant difference was found in gender, age, lymphatic, venous, and perineural invasion, pT, pN, pM and TNM staging when the two groups were compared. No significant difference was found between the overall survival rates of both groups. In EBSCC cases, cyclin A expression was positive in 94.1% of the cases, while 5.9% showed no expression. Cyclin B1 expression showed positivity in 23.6% of cases and 76.4% showed no staining. Most of the cases (70.6%) showed no cyclin D1 expression, while 29.4% were considered positive. EGFR expression was positive in 52.9% and negative in 47.1% of the cases. Expression of HER2 was observed in a small proportion of the cases (29.4%), when compared to those (70.6%) with no expression. Considering the KI-67 labeling index, most of the cases (76.4%) were classified as Low Proliferation, while only 11.8% were considered as High Proliferation. Among the ESCC cases, 30.0% were considered negative for cyclin A expression and 70.0% cases were positive. For cyclin B1, 18.4% were positive and 81.6% showed no expression. Cyclin D1 showed no staining in 85.4% of the cases, while 14.6% were positive. EGFR expression was positive in 80.9% and negative in 19.1% of the cases. HER2 expression was negative in 52.8% and 44.7% were considered positive. Analysis of Ki-67 expression showed that most of the cases (70.8%) were classified as Low Proliferation, while 29.2% were considered as High Proliferation. Comparing the markers expression between the two groups, EGFR (p=0.025) and cyclin A (p=0.029) showed significant differences. Positive EGFR expression was more frequent in the usual ESCC than in the EBSCC group. For cyclin A, positivity was more frequent in the EBSCC group, when compared to the usual ESCC cases. Regarding the other markers, there was no significant difference between the two groups. Although some observed differences did not achieve statistical significance, this work has further highlighted possible differences between the molecular pathogenesis of BSCC and SCC. Citation Format: Yukie Sato-Kuwabara, Juliano Jampietro, José Ivanildo Neves, Felipe José F Coimbra, Carolina Parucce, Wilson Luís Costa Junior, Fernando Augusto Soares. Comparative immunohistochemical study of basaloid and usual squamous cell carcinoma of the esophagus. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 571. doi:10.1158/1538-7445.AM2014-571