Carcinoma and Prostate Cancer
Adenocarcinoma (or carcinoma for short) is the type of cancer developing from epithelial cells, the type of cell which lines internal organs and bodily surfaces. If it weren't for the epithelial cell we'd all be a soft gelatinous mass of slimy goo. Epithelial cells compose the inner and outer surface of our organs so that things stay separate and generally useful.
The prostate supplies most of the ejaculatory stuff that nourishes the sperm on their fantastic voyage up the female reproductive tract into prospective fatherhood. The other main portion of the ejaculate is the sperm themselves which are produced in the testes and which swim up the vas deferens to hang out in the seminal vesicles until they get their marching orders during orgasm.
The prostate is sort of like the male breast, a hormonally influenced organ that produces a milky white substance. In fact, under the microscope, the breast tissue looks a lot like prostate tissue. Unlike breasts, prostates do not come in pairs and generally are not as fun to look at.
The prostate contains thousands of microscopic passageways that join one another and connect to the urethra, or pissing tube that runs from the bladder, through the middle of the prostate, and then through the penis. These microscopic passageways are lined by epithelial cells which in fact produce the prostatic contribution to the ejaculate. In addition to nutrition for the spermies, the prostatic epithelial cells produce a large amout of PSA.
The purpose of the PSA is to liquify the gelatinous goop of the ejaculate so that the sperm can swim unhindered once they have been splurted closer to their goal. Although PSA made in the epithelial cells is meant to be released into the prostatic tubes and eventually leave the body under pleasurable circumstances, some of it leaks into blood circulating through the prostate and makes its way into the bloodstream where it can be detected by the PSA blood test.
Epithelial cells need to replace themselves because like all things that provide a useful function, they wear out and die. New prostate cells are produced by maturation and division of certain cells (basal cells) which lie beneath the epithilial cells sort of the way adult teeth lie underneath baby teeth waiting for their chance to erupt into the world.
Cancer starts when the dividing mechanism get out of kilter and the cells multiply, not to serve as useful replacements, but just for the hell of it. The cells divide and multiply at rate faster that they are needed. They accumulate in bunches and no longer form the tubules that God intended. They are no longer law-abiding prostate cells serving the needs of the postate and the general good of the body. They are now outlaw carcinoma (cancer) cells and pretty much do as they please.
During the early phase of most prostate cancers, the malignant cells are more akin to motorists who don't make a complete halt at a stop sign. Life and society gets on pretty well with these minor violations and no one seems to mind. Some cancers though, perhaps because they have gotten away with minor violations, develop the chutzpah (or genetic mutations) to more flagrantly ignore the rules of prostatic society.
These tumor cells become less differentiated (i.e., less like their law-abiding benign brethren) and degrade into more aggressive (higher grade) tumors. They begin to look uglier under the microscope. Most prostate cancers accumulate their share of minor traffic offenses and are content to stay where they are in their prostatic home. The ones that have meaner dispositions cause blood vessels to form in order to feed them more nutrients.
Particularly nasty prostate cancer cells may infiltrate into the blood stream and thereby gain access to other parts of the body. This may lead to the formation of tumors in distant parts of the body, a process called metastasis.
As the tumor gets bigger it takes up a larger portion of the prostate and eventually may spread outside the border of the prostate (the "capsule") and eventually into adjacent organs (local spread) or distant organs (metastatic spread). The extent to which the cancer spread is called the stage. Staging is determined by a variety of tests including the digital rectal exam and imaging studies (ultrasound, MRI, bonescan, Prostascint).
The grading of the tumor is a measure of the aggressiveness of the tumor as it appears under the microscope. Gleason grading refers to the pattern of the tubular structures made by the malignant cells. Nuclear grading refers to specific features of the malignant cells and is related to DNA ploidy.