Question

In adults, over 90% of all cancers arise in epithelium. Such cancers are called carcinomas, or adenomas (adenocarcinomas) if they arise in glandular epithelia. In fact, cancers of the skin, lung, colon, breast, and prostate are all in these categories. Why do you think this is so?

Accepted Answer

Step 1: Understand the nature of epithelial tissue. Epithelial tissues line the surfaces and cavities of organs and structures throughout the body, forming protective barriers and involved in absorption, secretion, and sensation. Step 2: Recognize that epithelial cells have a high rate of turnover. Because they are constantly exposed to environmental damage and wear, epithelial cells frequently divide to replace lost or damaged cells, increasing the chance of DNA replication errors. Step 3: Consider that frequent cell division increases the likelihood of mutations. Each time a cell divides, there is a risk of mutations occurring in the DNA, which can accumulate and potentially lead to cancerous transformations. Step 4: Note that epithelial tissues are often exposed to carcinogens. For example, skin epithelium is exposed to UV radiation, lung epithelium to inhaled toxins, and colon epithelium to dietary carcinogens, all of which can damage DNA and promote cancer development. Step 5: Conclude that the combination of high cell turnover, exposure to environmental carcinogens, and the critical functions of epithelial tissues explains why over 90% of adult cancers arise in epithelial cells, leading to carcinomas and adenocarcinomas.

In adults, over 90% of all cancers arise in epithelium. Such cancers are called carcinomas, or adenomas (adenocarcinomas) if they arise in glandular epithelia. In fact, cancers of the skin, lung, colon, breast, and prostate are all in these categories. Why do you think this is so?

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Concetti chiave

Epithelial Cell Proliferation and Turnover

Exposure to Environmental Carcinogens

Glandular Epithelium and Adenocarcinomas