“Analysis of immunohistochemical expression of epidermal growth factor receptor in oral squamous cell carcinoma using tissue microarray technology and whole sections:” A comparative study

BACKGROUND: Oral squamous cell carcinoma (OSCC) accounts for more than 90% of all oral cancers. Epidermal growth factor receptor (EGFR) dysregulation is associated with essentially all of the key features of cancer. Tissue microarrays (TMAs) allow the simultaneous analysis of many tumours using small-diameter cores sampled from larger blocks of tissue. Hence present study was taken up to validate TMA technology. AIMS AND OBJECTIVES: To analyse and compare the immunohistochemical (IHC) expression of EGFR in OSCC using TMA technology and in whole tissue sections. MATERIALS AND METHODS: Study included 34 cases of OSCC.Three tissue cores, each 1 mm in diameter were placed into a recipient paraffin block using a precision microarray instrument finally containing 102 spots. EGFR expression was analysed. Agreement between whole sections and TMA scores was analysed using Cohen's weighted Kappa. RESULTS: EGFR expression was seen in 61.8% of whole section cases. In TMA out of 102 cores 75.50 % of the disks were confirmed to represent an adequate amount of tumor tissue. In TMA 48.5% cases showed EGFR expression.The EGFR expression of whole. CONCLUSION: Some OSCC express high EGFR and this expression may be an independent Wfactor of certain clinico-pathological variables. TMA may be used as an adjunct with conventional method of evaluation of OSCC especially in larger sample sized studies keeping in mind its limitations.