β-Catenin Alterations in Squamous Cell Carcinoma of the Lip

Does Loss of Immunohistochemical Expression of Glypican 3 in Oral Squamous Cell Carcinoma Play a Role in the Wnt/β-catenin Signaling Pathway?

Glypican 3 (GPC3) is a cell membrane protein and plays a dual role, as a tumor suppressor and oncogene, depending on its structure. It is known to regulate the Wnt/β-catenin signaling pathway and affect cell growth and proliferation. β-catenin plays a major oncogenic role in progression of oral squamous cell carcinoma (OSCC); thus, this study aimed to explore the relationship between β-catenin and GPC3 in OSCC. Immunoexpression of GPC3 and β-catenin was evaluated semiquantitatively in tumor tissue (n=80) and normal oral mucosa tissue (n=20). For GPC3, the percentage of stained cells and the staining intensity were assessed. For β-catenin, the percentage of stained cells, localization, and intensity of staining were assessed at the tumor-invasive front. The Pearson correlation was used to determine the correlation between the GPC3 and β-catenin immunoreactivity. Significantly decreased expression of GPC3 (P=0.008) and a highly significant difference in the case of localization of β-catenin (P=0.0001) were observed in OSCC when compared with normal oral mucosa. Cytoplasmic expression with a shift of β-catenin expression to the nucleus was seen in OSCC in comparison with primarily membranous and membranous and cytoplasmic staining in normal mucosa. A significant difference was observed with respect to localization of stain, with β-catenin staining moving to the nuclear compartment with an increase in the tumor grade (P=0.011). No correlation was observed between β-catenin and GPC3 expression in OSCC cases. It is concluded that loss of expression of GPC3 in OSCC compared with normal oral mucosa indicates that it plays the role of a tumor suppressor gene in OSCC and its expression is therefore silenced in OSCC.

Protein Expression of Stromelysin-2 in Head and Neck Squamous Cell Carcinomas

BACKGROUND

Some matrix metalloproteinases (MMPs) are involved in invasion and metastasis of head and neck squamous cell carcinoma (HNSCC). However, there are few studies on association between stromelysin-2 (ST-2) and invasive behavior of HNSCC. The purpose of this study was to investigate Stromelysin-2 expression by immunohistochemistry.

MATERIALS AND METHODS

This study was conducted on 81 specimens, including 61 HNSCC and 20 non neoplastic epithelium. Sections with 5 micron thickness were prepared and stained with immunohistochemistry technique. Then expression of ST-2 was evaluated according to percentage of stained cells and intensity of staining. Data were analyzed by SPSS (V.21) using Kruskal-Wallis and Tukey tests (P<0.05).

RESULTS

The 61 HNSCC specimens were grades I 36.1%, II 34.4% and III 29.5%. The level of ST-2 expressions were moderate (++) and intensive (+++) in 21.3% and 78.7% of tumors, respectively. The ST-2 expression level was only significant between the tumors with grade I and grade III (P=0.016). Tumors presented ST-2 expression with staining intensity of mild 6.6%, moderate 26.2% and strong 67.2%. Staining intensity of ST-2 in grade I tumors was significantly lower than grade II and grade III (P<0.05), and there was no significant difference between grades II and III (P=0.99).

CONCLUSIONS

According to this study, the expression of ST-2 is associated with histopathological grade and tumor differentiation in HNSCCs.