CLASSIFICATIONS OF CANCER
There are many types of cancer. A classification system was developed based on the type of cell that produced the cancer. The majority of all cancers fall under four headings: carcinomas, sarcomas, lymphomas, and leukemias.
• Carcinomas involve the epithelial cells (cells lining the body).These include the outer layer of the skin, the membranes lining the digestive tract, the bladder, the womb, and any duct or tube that goes through organs in the body.
• Sarcoma is cancer of the soft tissues of the body, such as muscle; fat;nerves; tendons; blood and lymph vessels; and any other tissues that support, surround, and protect the organs in the body. Soft-tissue sarcomas are uncommon. Sarcomas can also occur in bone rather than soft tissue and primarily in the legs.
• Lymphomas are cancer of the lymphoid tissue. This includes the lymph nodes, bone marrow, spleen, and thymus gland.
• Leukemias develop from the white blood cells and also affect thebone marrow and spleen.
The site where the cancer is located will become part of the diagnosis, such as basal cell carcinoma.
Skin cancer is becoming more prevalent. There are three types of skin cancer: basal cell, squamous cell, and melanoma. Basal cell carcinoma is the most common form of skin cancer, affecting the outer skin layer and caused by exposure to sunlight. Those at high risk have fair skin, light hair, and blue, green, or gray eyes and spend considerable leisure time in the sun. Squamous cell carcinoma affects the squamous cells that are in the upper layer of the skin. Most cases arise from chronic exposure to sunlight, but may also occur where skin has been injured—burns, scars, or long-standing sores. Melanoma is the most serious and deadliest form of skin cancer and originates in the cellsthat produce the pigment melanin, which colors our skin, hair, and eyes. The majority of melanomas are black or brown, but some melanomas occasionally stop producing pigment and are skin colored, pink, red, or purple. If caught early, melanoma is almost 100% curable; therefore a yearly exam by a derma-tologist is recommended for early diagnosis of all skin cancers.
The following viruses have been linked to cancer: Epstein Barr, hepatitis B, and human papilloma virus (HPV). Epstein Barr may cause nasophar-yngeal cancer, T-cell lymphoma, Hodgkin’s disease, and gastric carcinoma. There is an anticancer vaccine available to prevent hepatitis B and its serious consequences—liver cancer. A vaccine is now available to prevent cervical cancer caused by HPV. Cancer research is ongoing and continues in these and other areas.