Squamous cell carcinoma originates from malignant transformation of which cells?

Squamous cell carcinoma originates from malignant transformation of which cells?

• A. Melanocytes.
• B. Langerhans cells.
• C. Keratinocytes.
• D. Fibroblasts.

Answer: (C)

Squamous cell carcinoma arises from malignant transformation of keratinocytes, the predominant cells of the stratified squamous epithelium in skin and mucosal surfaces. Keratinocytes originate in the basal layer, proliferate, and differentiate into mature, keratin-producing cells as they migrate toward the surface. When mutations accumulate—often driven by UV exposure in sun-exposed skin—these keratinocytes become dysplastic and can invade, leading to SCC. Histologically, squamous differentiation is evidenced by features such as keratin pearls and intercellular bridges. Melanocytes are pigment-producing cells; tumors from them are melanomas. Langerhans cells are dendritic antigen-presenting cells in the epidermis; neoplasms from them are not squamous cell carcinomas. Fibroblasts reside in the dermis and can give rise to fibrosarcomas, not SCC.

Squamous cell carcinoma arises from malignant transformation of keratinocytes, the predominant cells of the stratified squamous epithelium in skin and mucosal surfaces. Keratinocytes originate in the basal layer, proliferate, and differentiate into mature, keratin-producing cells as they migrate toward the surface. When mutations accumulate—often driven by UV exposure in sun-exposed skin—these keratinocytes become dysplastic and can invade, leading to SCC. Histologically, squamous differentiation is evidenced by features such as keratin pearls and intercellular bridges.

Melanocytes are pigment-producing cells; tumors from them are melanomas. Langerhans cells are dendritic antigen-presenting cells in the epidermis; neoplasms from them are not squamous cell carcinomas. Fibroblasts reside in the dermis and can give rise to fibrosarcomas, not SCC.