Carcinoma cells are cancer cells that originate from epithelial cells, which are the cells lining various organs and tissues in the body. Epithelial cells form the outer layer of the skin, as well as the lining of internal organs, such as the lungs, liver, kidneys, and digestive tract. Carcinomas are the most common type of cancer, accounting for approximately 85% to 90% of all cancer cases.
Carcinoma cells often exhibit abnormal cellular characteristics, including uncontrolled proliferation, the ability to invade surrounding tissues, and metastasize to distant organs through the bloodstream or lymphatic system. They may also develop resistance to apoptosis (programmed cell death), allowing them to survive and continue to divide even in unfavorable conditions.
There are several subtypes of carcinomas, based on the specific type of epithelial cell affected and the organ involved. Some common types of carcinomas include:
- Adenocarcinoma: This type of carcinoma arises from glandular epithelial cells, which produce and secrete various substances. Examples include breast, prostate, colon, and lung adenocarcinomas.
- Squamous cell carcinoma: This cancer develops from squamous epithelial cells, which form the outer layer of the skin and the lining of some internal organs. Squamous cell carcinomas can occur in the skin, lung, esophagus, and other sites.
- Transitional cell carcinoma: Also known as urothelial carcinoma, this cancer originates from the transitional epithelium, which lines the urinary tract, including the bladder, ureters, and kidneys.
- Basal cell carcinoma: This is the most common type of skin cancer and originates from the basal layer of the epidermis.
Carcinoma cells are often studied in the laboratory using established cancer cell lines, which serve as models for investigating the mechanisms of cancer development, progression, and response to treatments.
