Comparison of ayoub shklar stain and routine haematoylin and eosin stain for the keratin identification in kcot–a pilot study

Keratins are one of the major and key structural proteins, found at their highest concentration and diversity in the keratinocytes of cutaneous as well as oral epithelium and accounts for almost 80% of the total protein content in differentiated cells of stratified epithelia. In the 1900s, keratins were believed to be the proteins, which could be extracted from the various epidermal modifications of animals such as wool, horns, claws, etc.1,2 Subsequently, with advancement in research and advent of 21st century technologies, keratin(cytokeratins) are now considered as intermediate filament proteins with specific physicochemical properties, found in any vertebrate epithelia.2 They are part of the multi-gene family of proteins, occurring in basic and acidic protein pairs with varied expression pattern in different types of epithelia, as well as different layers of a single stratified epithelium. The main function of cytokeratins along with microtubules and microfilaments is to provide with structural integrity and mechanical resiliency to all the eukaryotic cells. The oral epithelium can be categorized into keratinized stratified epithelia (ortho and parakeratinized) and non-keratinized epithelia based on the presence or absence of keratinization. Keratinization or cornification involves the process of cytodifferentiation of the keratinocytes, starting from their post formative state, i.e., stratum basale to the final differentiated state of toughened cornified cells filled with keratin filaments found in the surface layer, i.e., stratum corneum.