<prompt> For detection of carcinoma lip, stain used is?GiemsaCrystal violetToulidine blueHematoxylin and eosin  <response>: Ans. c Toulidine blueRef: Early Diagnosis and Treatment of Cancer Series: Head and Neck Cancers, Wayne Koch Pg. 54Toluidine 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. 