The human keratins are intermediate filament proteins found in epithelial cells, showing high molecular diversity. They are expressed in specific patterns related to epithelial type and differentiation stage. About half of all keratins are restricted to hair follicle compartments. Keratins are important for epithelial mechanical stability and integrity, and some have regulatory roles in intracellular signaling. The new consensus nomenclature has been established for human keratins, with 54 functional genes. These keratins are important in tumor diagnosis, particularly in carcinomas, due to their characteristic expression patterns. Keratins also play roles in cell cycle regulation, apoptosis, and wound healing. They are involved in various epithelial functions, including structural support, cell-cell adhesion, and basement membrane attachment. Keratin expression patterns are used in diagnosing epithelial tumors and differentiating between various types of carcinomas. Keratins are also used as markers in clinical settings, such as monitoring cancer progression and response to therapy. The keratin family has diverse functions, including structural support, mechanical stability, and signaling roles. They are expressed in various epithelial tissues and are involved in epithelial differentiation and tumor pathology. Keratin expression patterns are important for diagnosing and classifying tumors, and they are used in clinical applications such as monitoring cancer load and response to treatment. The keratin family includes various types, such as K8/K18, K7/K19, K20, K5/K14, K6/K16, and K15, each with specific functions and expression patterns in different tissues and cells. These keratins are important in both normal and pathological conditions, and their study has provided insights into epithelial biology and disease mechanisms.The human keratins are intermediate filament proteins found in epithelial cells, showing high molecular diversity. They are expressed in specific patterns related to epithelial type and differentiation stage. About half of all keratins are restricted to hair follicle compartments. Keratins are important for epithelial mechanical stability and integrity, and some have regulatory roles in intracellular signaling. The new consensus nomenclature has been established for human keratins, with 54 functional genes. These keratins are important in tumor diagnosis, particularly in carcinomas, due to their characteristic expression patterns. Keratins also play roles in cell cycle regulation, apoptosis, and wound healing. They are involved in various epithelial functions, including structural support, cell-cell adhesion, and basement membrane attachment. Keratin expression patterns are used in diagnosing epithelial tumors and differentiating between various types of carcinomas. Keratins are also used as markers in clinical settings, such as monitoring cancer progression and response to therapy. The keratin family has diverse functions, including structural support, mechanical stability, and signaling roles. They are expressed in various epithelial tissues and are involved in epithelial differentiation and tumor pathology. Keratin expression patterns are important for diagnosing and classifying tumors, and they are used in clinical applications such as monitoring cancer load and response to treatment. The keratin family includes various types, such as K8/K18, K7/K19, K20, K5/K14, K6/K16, and K15, each with specific functions and expression patterns in different tissues and cells. These keratins are important in both normal and pathological conditions, and their study has provided insights into epithelial biology and disease mechanisms.