For detection of carcinoma lip, stain used is?

Ans. (c) Toulidine blue(Ref: Early Diagnosis and Treatment of Cancer Series: Head and Neck Cancers, Wayne Koch Pg. 54)*Toluidine blue stain is used as a marker to differentiate lesions at high risk of progression in order to improve early diagnosis of oropharyngeal carcinomas.*Toluidine blue, an acidophilic metachromatic dye of thiazine group selectively stains acidic tissue components (sulfates, carboxylates and phosphate radicals), thus staining DNA and RNA.