Epithelial cell? I'm really confused can somebody pleeeaaassseee help me!?

Question

in adult humans, most cancers are carcinomas or adenocarcinomas involving various types of epithelial tissue cells. These include cancers of the skin, lung, colon, breast, and prostate. Why do you think that most cancers arise from epithelial cells?

I asked my teacher and he told me it had to do with their location and cellular process but i'm still confused

Answer 1

That's a great question. Epithelial cells are particularly prone to becoming cancerous because they are the cells that tend to be exposed to the harshest environments. Furthermore, most cancers of epithelial cells tend to occur in areas where the epithelium is transitioning from one type to another. In these areas, the cells have unusual properties and are more prone to break away.

Most cells have very specific mechanisms preventing them from dividing when they need not to, but cells in these vague transition areas appear to be less regulated in that manner, and its not known for certain why (but there are a lot of theories). Also, persistent damage to an epithelium will cause sections of cells to become a different, tougher type of epithelium, thus creating another one of these transition areas. This often preceeds cancers of the mouth, esophagus, and lungs. For example, persistent damage to the lining of the esophagus from acid reflux will cause sections to become a tougher epithelium, creating a new set of dangerous transition areas.

It's okay that you're confused, you should be, because cancer is a subject no one really understands completely!

Answer 2

Epithelial cells are the source of the majority of cancers; the investigators thus concentrated on factors controlling epithelial cell organization. Epithelial tissues are specialized for managing the flow of substances into and out of the body and for protecting underlying organs. To form these tissues, epithelial cells are tightly interconnected in sheets that line hollow organs and glands, including the breast, prostate, colon, and lung, as well as external surfaces of the body.

Epithelial cell organization is determined by a specialized structure known as the basement membrane, a form of the ubiquitous extracellular matrix (ECM) that acts as both a structural scaffold for cells in a tissue and a medium through which the cells communicate. Breakdown of the basement membrane is associated with the spread of tumors; in earlier studies with transgenic mice, Bissell and her colleagues, including UCSF's Werb, showed that loss of integrity of the basement membrane can itself cause tumors. But the mechanism was not understood.

Among the chief agents controlling the configuration of the basement membrane are the matrix metalloproteinases, digestive enzymes that normally act as bulldozers to clear the way for building new organ structures or repairing old ones. Breast tumors have an increased amount of MMPs, however, and this promotes the spread of tumors by degrading the basement membrane and digesting the contacts that bind the epithelial cells into sheets.

In cancers MMPs also wreak havoc in another way, as Bissell and her colleagues showed previously: MMPs induce the so-called epithelial-mesenchymal transition (EMT). This transition from one cell state to another causes epithelial cells to disassociate from their neighbors, break free, and acquire the ability to move through the body. In the embryo, EMT is essential for normal organ development. In breast cancer, however, the process renders tumor cells mobile and helps them penetrate barriers like the walls of lymph and blood vessels, facilitating metastasis.

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Answer 3

http://en.wikipedia.org/wiki/Epithelial_cell