Types of Mesothelioma

Mesothelioma can attack the pleural lining around the lungs. It can also attack the peritoneum, a tissue that surrounds the GI tract. Mesothelioma can attack the stomach lining, other internal organs, or even the pericardium (the tissue sac covering the heart). Thus, mesothelioma can be generally classified into the following types:

Pleural — 75%
Peritoneal — 10%
Pericardial — 5%
Mesothelioma can also be classified by the cancer type rather than the location of the cancer:
Epithelioid — most common.
Sarcomatoid — most severe.

Cancer and Mesothelioma

The most common form of cancer caused by asbestos is mesothelioma, a rare cancer that is very rarely cured. The only proven cause of mesothelioma is exposure to asbestos.

An estimated 20 to 30 percent of people diagnosed with mesothelioma have no knowledge of prior exposure to asbestos. But the prior popularity of asbestos as a building material may shed some light on a person's ability to identify the source of their exposure to asbestos.

Mesothelioma typically attacks the thin membranous lining of the lungs, abdomen, or heart, known as the mesothelium. It is estimated that 2,000 to 3,000 new cases of mesothelioma are reported each year. The symptoms of mesothelioma typically arise 20 to 50 years after exposure, which makes it difficult to diagnose the countless cases lying dormant across the country. For more information about mesothelioma

Cancer Stages

The stage of a cancer is a descriptor (usually numbers I to IV) of how much the cancer has spread. The stage often takes into account the size of a tumor, how deep it has penetrated, whether it has invaded adjacent organs, how many lymph nodes it has metastasized to (if any), and whether it has spread to distant organs. Staging of cancer is important because the stage at diagnosis is the most powerful predictor of survival, and treatments are often changed based on the stage.


Overall Stage Grouping is also referred to as Roman Numeral Staging. This system uses numerals I, II, III, and IV (plus the 0) to describe the progression of cancer.

Stage 0 carcinoma in situ.
Stage I cancers are localized to one part of the body.
Stage II cancers are locally advanced, as are stage III
Stage III cancers. Whether a cancer is designated as Stage II or Stage III can depend on the specific type of cancer; for example, in Hodgkin's Disease, Stage II indicates affected lymph nodes on only one side of the diaphragm, whereas Stage III indicates affected lymph nodes above and below the diaphragm. The specific criteria for Stages II and III therefore differ according to diagnosis.
Stage IV cancers have often metastasized, or spread to other organs or throughout the body.
Within the TNM system, a cancer may also be designated as recurrent, meaning that it has appeared again after being in remission or after all visible tumor has been eliminated. Recurrence can either be local, meaning that it appears in the same location as the original, or distant, meaning that it appears in a different part of the body.

Mesothelioma Lung Cancer

Mesothelioma and lung cancer are both serious illnesses, but they are not the same. Mesothelioma – sometimes called “asbestos lung cancer” – is really not a form of lung cancer because it does not develop in the tissue of the lungs. Instead, it is a cancer of the lining that surrounds the lung (the “pleura”).

Mesothelioma is caused almost exclusively by asbestos exposure. It is considered a “signature disease” for asbestos exposure, which means that, if you have mesothelioma, it can be assumed that you had exposure to asbestos at some point in your life. Smoking does not cause mesothelioma.
Lung cancer can be caused by asbestos exposure; it can also be caused by smoking. In fact, someone who smokes and was exposed to asbestos has a much higher risk of getting lung cancer. See Asbestos and Smoking.

Cloning: There’ll Never Be Another You

Depending upon your point of view, cloning organisms may sound like a
nightmare or a dream come true. Whatever your opinion, cloning is most definitely
not science fiction; decisions about experimental cloning are being
made right now, every day. This chapter covers cloning: what it is, how it’s
done, and what its impact is from a biological point of view. Cloning (like just
about everything else in science) isn’t as simple as the media makes it sound.
In this chapter, you get to know the problems inherent in clones along with
the arguments for and against cloning (not just of humans — of animals and
plants, too). Get ready for an interesting story. Remember, it ain’t fiction!

cloning

The other use of the word cloning means to make a copy of an entire organism
as a reproductive strategy. When referring to a whole creature as opposed to
DNA, a clone is an organism that’s created via asexual reproduction, meaning
offspring are produced without the parent having sex first. Cloning occurs naturally
all the time in bacteria, plants, insects, fish, and lizards. For example,
one type of asexual reproduction is parthenogenesis, which occurs when a
female makes eggs that develop into offspring without being fertilized by a
male (for some of you female readers, I’m sure this sounds very appealing). So
if reproduction by cloning is a natural, normal biological process, what’s the
big deal with cloning organisms using technology?

Attack of the Clones

A clone is simply an identical copy. The word is used as both a verb, as in “to
clone” (make one) and a noun, as in “a clone” (have one or be one).
Genetically, the word clone can have two meanings. When geneticists talk
about cloning, they’re most often talking about copying some part of the DNA
(usually a gene). Geneticists clone DNA in the lab every day — the technology
is simple, routine, and unremarkable.