P237 The expression of carbonic anhydrase 9 (CA9) is associated with postoperative recurrence and poor prognosis in surgically treated oral squamous cell carcinoma

Abstract Background: Carbonic anhydrase 9(CA9), as a member of the carbonic anhydrase enzyme family, was an endogenous marker of hypoxia. Previous studies suggested CA9 expression was correlated with poor prognosis in multiple types of malignancies. The purpose of current study was to evaluate the role of CA9 as a prognostic marker in sinonasal squamous cell carcinoma(SNSCC).Patients and methods: We assessed the immunohistochemical expression of CA9 in 63 tumor specimens of patients who underwent curative surgery and evaluated the relationship between the expression levels and clinicopathological factors as well as outcome.Results: We observed positive expression of CA9 in 21(33.3%) patients. Positive expression of CA9 in patients with SNSCC was significantly correlated with local recurrence (p=0.016) and both overall survival (OS) (p=0.003) and disease-free survival (DFS) (p=0.002). In Cox's multivariate analysis, CA9 expression was an independent negative prognostic factor for OS (p=0.027) and DFS (p=0.018).Conclusions: Our findings demonstrated that CA9 overexpression could be used as an independent prognostic biomarker and therapeutic target in SNSCC.

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Expression Of Gamma Glutamyl Hydrolase And Carbonic Anhydrase 9 In Oral Squamous Cell Carcinoma And Their Association With Extracapsular Spread

IIUM Medical Journal Malaysia ◽

10.31436/imjm.v16i2.1070 ◽

2017 ◽

Vol 16 (2) ◽

Author(s):

Nor Aszlitah Burhanudin ◽

Thomas George Kallarakka

Keyword(s):

Squamous Cell Carcinoma ◽

Oral Squamous Cell Carcinoma ◽

Carbonic Anhydrase ◽

Cell Carcinoma ◽

Squamous Cell ◽

Normal Mucosa ◽

Chi Square ◽

Extracapsular Spread ◽

Gamma Glutamyl ◽

Carbonic Anhydrase 9

Introduction: Extracapsular spread (ECS) is one of the most important prognostic factors in oral squamous cell carcinoma (OSCC). Gamma Glutamyl Hydrolase (GGH) is a lysosomal enzyme which is involved in folate homeostasis. It is overexpressed in several human malignancies but its role in OSCC has never been reported. Carbonic Anhydrase 9 (CA9) is a transmembrane glycoprotein and is related to hypoxia. High expression of CA9 has been associated with poor prognosis in several tumours including OSCC. This study was aimed to investigate the expression of GGH and CA9 in OSCC and their potential use as biomarkers to predict ECS. Materials and Methods: Immunohistochemical staining with GGH and CA9 markers were performed in 35 cases of OSCC (19 with ECS and 16 without ECS) and 5 cases of normal mucosa. A semi-quantative index was used for immunoscoring. Association between the expression of these markers and ECS status were analyzed using chi-square test. Results: Immunohistochemical results indicated that GGH and CA9 were upregulated in OSCC. High GGH and CA9 expression were significantly associated with ECS (p<0.05). Combination of GGH and CA9 showed greater prognostic accuracy as compared to the individual markers. Conclusion(s): Both separately and in combination GGH and CA9 offer potential as prognostic biomarkers in OSCC and was thus reliable in segregating the OSCC cases based on ECS status.

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