Expression profiles of selected genes in tumors and matched surgical margins in oral cavity cancer: Do we have to pay attention to the molecular analysis of the surgical margins?

Background. Head and neck squamous cell carcinomas (HNSCCs) are associated with an interplay between genetics and the environment; they account for 3% of all diagnosed malignant tumors in men and 2% of those in women. Objectives. The aim of the study was to analyze the significance of TIMP3, SFRP1, SFRP2, CDH1, RASSF1 , RORA, and DAPK1 gene expression in head and neck squamous cell carcinoma tumors, and in matching surgical margin samples. We also analyzed the association between clinical parameters and the expression of the selected genes. Material and methods. Following surgical resection, 56 primary HNSCC tumors and matching surgical margin samples were collected from patients at the Clinic of Ontological and Reconstructive Surgery of Maria Sklodowska-Curie Memorial Cancer Center and the Institute of Oncology in Gliwice, Poland. The gene expression levels were analyzed by quantitative reverse transcription (qRT)-PCR. Results. SFRP1 gene expression was statistically significantly lower in the tumor samples than in the surgical margins (0.30 +/- 0.36 vs 0.62 +/- 0.36; p <0.01). No correlation was found between gene expression and clinical parameters, except DAPK1, where low expression correlated with alcohol abuse (0.85 +/- 1.19 vs 1.97 +/- 3.22; p = 0.074). Moreover, patients with G3 grade tumors, i.e., poorly differentiated tumors, had significantly higher values of DAPK1 gene expression than the G1 (well-differentiated tumors) and G2 (moderately differentiated) groups. Conclusions. There are many different reasons and concepts for altered gene expression in tumors and surgical margin tissue. Tumor heterogeneity and its microenvironment are undoubtedly linked to the biology of HNSCC. In order to understand specific tumor behavior and the microenvironment, further studies are needed. To find markers connected with cancer development and to provide insight into the earliest stages of cancer development, attention should also be focused on molecular analysis of the surgical margins.