HB+Cancer+Article

=April 3, 2007= =A Mutinous Group of Cells on a Greedy, Destructive Path= =By NATALIE ANGIER=

The article begins by mentioning two important people with cancer. Who is Elizabeth Edwards? Who is Tony Snow?

 * Mrs. Edwards, the 57-year-old wife of the presidential candidate John Edwards. Elizabeth Edwards (born Mary Elizabeth Anania on July 3, 1949, in Jacksonville, Florida) is an attorney. She announced that the cancers for which she had previously been treated had returned and metastasized: in her case, spreading from breast to bone.
 * Mr. Snow, the 51-year-old press secretary to President Bush. Between his two White House stints, Snow was a broadcaster and newspaper columnist. He announced that the cancers for which he had previously been treated had returned and metastasized: in his case spreading from colon to liver.

What is a metastatic cancer cell?

 * 90 percent of deaths from cancer are the result of metastases, of malignant cellular outposts proliferating far from the neoplastic mass that spawned them. They are barbarians, the colonist cells, co-opting all nutrients in their adopted organ and starving their normal neighbors of air, sugar and salts, and blocking traffic and clogging conduits, and finally, when their greed exceeds their easy grab, tearing open surrounding cells and feasting like cannibals on the meat of their fellows.

Why does the author call cancer cells barbarians and cannibals?

 * Barbarians in that they starve air from their neighbors and cannibals in eating the neighboring cells.

What do we know about the events that transform a normal cell to a cancer cell?

 * "Biologists know quite a bit about the steps that transform a normal cell into a cancer cell, a cell that lawlessly divides and gives rise to a primary tumor. They have identified genetic mutations and chromosomal aberrations that prompt cells to think they are being stimulated by growth hormones when they are not, that stifle safety signals meant to keep cell division in check, and that shore up the tips of chromosomes and so immortalize cells that otherwise would be slated to die."

Why is harder to study metastatic cancer cells?

 * "Researchers’ grasp of metastasis, by contrast, remains relatively sketchy, one reason being that whereas the initial stages of malignant transformation can be analyzed in vitro, in the controlled setting of cultured cells, metastasis — which is Greek for “beyond static” — is a matter of cells on the move and ultimately must be studied in vivo, in the bewildering wilderness of the body."

How many cells do primary tumors shed each day (in a rodent)? Yet how many metastatic tumors do these rodents have?

 * in experiments with mice carrying bulky tumors of a billion cells each, perhaps a million cancer cells are seeded into the rodents’ circulation each day, “yet the visible metastases formed in such animals may be counted on the fingers of one hand.”

Describe two ways metastatic cells can travel through the body avoiding detection from our immune system.

 * To survive the journey, malignant cells must reinvent themselves as parasites. A few manage to slim down to almost bacterial dimensions by pinching off unnecessary hanks of their cytoplasm. Others take on what Dr. Weinberg calls “hitchhikers,” attracting an entourage of platelets and red blood cells to their surface “to escort them through the rapids into safe pools within tissues.”

Where is the first site (oasis for the cancer cell) that metastasis generally occurs? Why? Why is it an oasis? (What is an oasis?)

 * Such oases might be wound sites to which the chaperone platelets handily stick, enabling their companion cancer cells to gain their first toehold in virgin terrain — and to begin feeding on the rich broth of growth hormones and factors with which wound sites typically teem. In one 1993 report, Israeli oral surgeons described 55 cases of dental extractions in which the procedure was followed days to months afterward by the eruption of an ugly metastasis where the tooth had once been; for a third of the patients, the appearance of the gumline growth was the first sign that an internal organ was riddled with cancer.

What is a dormant micrometastasis? Why are they relevant to human health?

 * Yet even after malignant cells have settled onto a new site, their replicative success is hardly guaranteed. Most appear to either die or lapse into dormancy. Patients may harbor thousands or millions of these dormant micrometastases without suffering a fatal relapse of the disease. Evidence suggests that micrometastases will not attain macro dimensions unless, among other things, they adapt to their new surroundings and interact with their neighbors enough to exploit them. This helps explain why different types of primary tumors tend to metastasize to their “preferred” organ: cells learn a skill set from their tissue of origin, and some lessons are more easily applied to one novel setting than to another.

What evidence do we have that metastasis occurs in organs that are similar to the organ of the primary tumor? Give two examples.

 * Breast tumors, for example, are known to metastasize to bone tissue, where the invasive cells perversely take advantage of their ability to gather calcium ions for breast milk and apply it to the rampant dissolution of calcium-rich bone. Malignant melanoma spreads readily to the brain, presumably because neural tissue and the melanocytes that give rise to melanoma both arise from the same class of cells during gestation.