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Background:Apart from the role of mast cells in maintenance of homeostasis and inflammation, their association with tumors has been described recently. In several malignancies, mast cell density has been found to correlate with angiogenesis, increased risk of metastasis and poor prognosis.Aim:The aim of the following study is to compare the number, topography and distribution of mast cells between normal oral mucosa and oral oral squamous cell carcinoma (SCC) and study the significance of mast cells in development of oral SCC.Subjects and Methods:A prospective case-control study including 100 patients was conducted after obtaining informed consent and ethical committee clearance. Forty cases were normal controls and 60 cases had oral SCC. Biopsy was performed and both qualitative and quantitative study of mast cells was done. Statistical analysis was carried out using Statistical Package for Social Sciences (SPSS) 17.0 version (SPSS Inc., Chicago, IL, USA).Results:Buccal/labial mucosa was the most common site of lesion in SCC. Total mast cells count was a higher in SCC when compared with controls, which was a statistically significant (P < 0.001). SCC had significantly (P < 0.001) higher levels of degranulated mast cell.Conclusion:Role of mast cells in tumors may have direct clinical relevance and consequently, important clinical implications. Mast cells serves as a novel therapeutic target for cancer treatment and that inhibiting mast cell function may inhibit tumor growth.

We have characterized by capacitance-voltage and deep level transient spectroscopy measurements the only defect detected in Si-doped GaInP layers. This defect exhibits an ionization energy of 0.435 eV but is located only at ∼20 meV below the bottom of the conduction band. All its characteristics, i.e., energy level, apparent capture barrier, ionization energy, can be understood if the defect is a donor associated DX center. Its cross section for electron and hole capture have been measured. The effect of an electric field on the ionization energy confirms that the defect is indeed shallow and a donor.

We present a characterization of the defects created by electron irradiation at room temperature in n-type GaInP. Four electron traps, labeled E1–E4, and no hole traps have been detected using deep level transient spectroscopy in the temperature range 4–400 K. The corresponding energy levels and barriers associated with electron capture have been measured. The introduction rates, ranging from 4×10−3 to 0.4 cm−1, indicate that these defects are probably not primary defects but complexes resulting from the interaction of these primary defects between themselves or with impurities. This is not surprising, owing to the fact that defect annealing takes place below 300 K in InP.