Over-expression of hk7 in Head-Neck Cancer – Potential Diagnostic Value

Over-expression of hk7 in Head-Neck Cancer – Potential Diagnostic Value

Hong Zhao*, Ying Dong†, Alfred Lam*, Newell Johnson*, Judith Clements† and Jin Gao** *Centre of Medicine and Oral Health, Griffith University, Gold Coast; †Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia

Objectives: The hK7 or KLK7, one of the human kallikrein gene family members, takes part in skin desquamation. Emerging data demonstrate the involvement of kallikrein in various human diseases, including carcinoma. The aim of the study was to determine whether hK7 was detected in head and neck squamous cell carcinoma (HNSCC).

Methods: 105 archival paraffin blocks of HNSCC were obtained from Gold Coast Hospital. The expression of hK7 was studied by immunohistochemistry and clinicopathological analysis.

Results: In HNSCC, 33% were well-differentiated (n = 35), 56% were moderately-differentiated (n = 59) and 11% were poorly-differentiated (n = 11). The hK7 was faint expressed in basal layer of oral epithelium, but strongly in squamous cell carcinoma. The over-expression of hK7 was seen in 70% (n = 74) of carcinomas. The over-expression was more common in moderately or poorly-differentiated squamous cell carcinomas compared to the well-differentiated (77% versus 57%). Interestingly, this protein was significantly more expressed in the tumour mass that invaded in the area of deep tissues, such as muscles than in the area of surface tissue.

Conclusions: Multivariate analysis revealed diverse correlations between hK7 expression levels in nonmalignant and malignant tissues, and clinical parameters, including histology type, metastatic status, and grade. The findings provide new insight into kallikrein expression, for the first time, in hormone-independent HNSCC. Our data suggest that hK7 protein over-expression is associated with a more aggressive phenotype in oral squamous cancer cells. This study suggests the role of hK7 in oral tumorogenesis and potential diagnostic and prognostic value. Further studies are on going.