You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Squamous cell carcinoma can arise from-a) Long standing venous ulcersb) Chronic lupus vulgarisc) Rodent ulcerd) All of the above and explain in detail?
• It is a carcinoma of the cells of epidermis that usually migrate outwards to the surface.
• Originate from prickle cell layer; Seen in > 40 years of age
• MC skin cancer in darkly pigmented races
• 2nd MC skin cancer in light skinned races
• MC causative factor: Sunlight
• MC site: Ears, cheeks, lower lip and back of hands