Subject: Kaposi's Sarcoma Not a True Cancer, Research Suggests
Date: Published: 10/21/88 77 lines
Source:  Wall Street Journal.  Copyright Dow Jones & Co. Inc. 

    Technology:  
    Kaposi's Sarcoma
    Not a True Cancer,
    Research Suggests
    ---
    AIDS-Linked Tumor Studies
    Find New Growth Factor
    Triggers Lethal Disease
    ----  
    By Marilyn Chase
    Staff Reporter of The Wall Street Journal

    Research from the National Cancer Institute suggests that
 Kaposi's sarcoma, an AIDS-linked tumor, is provoked by a
 previously unknown growth factor and may not be a true
 malignancy at all.
    Prior to the outbreak of acquired immune deficiency
 syndrome in the early 1980s, Kaposi's sarcoma, or KS, was
 known as a slow-growing tumor found primarily in elderly
 Mediterranean men, with a more aggressive form found in
 Africa.
    However, the onset of AIDS brought a more virulent and
 fatal form of the sarcoma, which is marked by flat purplish
 plaques on the skin that may spread to the lungs or other
 internal organs.
    Research has been hampered by difficulty in culturing
 Kaposi's sarcoma cells in the laboratory.  But Robert C. Gallo
 and colleagues at the cancer institute reported in two
 related studies this week that they have isolated a new
 growth factor that trigger Kaposi's sarcoma.  The two reports
 are published in the current issue of the journal Science.
    "Our findings strongly suggest that the form of Kaposi's
 sarcoma occuring in AIDS patients, and perhaps forms of the
 disease that occur in individuals without AIDS, may be
 initiated by some signals such as infection with the AIDS
 virus that triggers release of the new growth factor," Dr. 
 Gallo said.
    The new growth factor -- so far called simply "X" or KS
 growth factor -- is released by T4-cells (white blood cells)
 when they are infected with HIV, the AIDS virus, or with
 other members of the family human retroviruses, including the
 leukemia viruses HTLV-1 and HTLV-2, the report said.
    The growth factor causes proliferation of certain cells,
 known as endothelial cells, which normally line internal body
 cavities such as the heart.  The cells multiply, and with them
 comes an abnormal growth of blood vessels, forming Kaposi's
 sarcoma lesions.  The Kaposi's sarcoma cells in turn release
 "a cascade" of other protein-based growth factors, Dr. Gallo
 said.
    The new findings also suggest Kaposi's sarcoma may not be
 a true malignancy.  It arises from several cell types unlike
 cancer, which arises from a single cell.  Also Kaposi's
 sarcoma is "multifocal" with a storm of lesions springing up
 simultaneously in several spots, in contrast to cancer's
 single-cell origin.  However, he emphasized, "not being fully
 malignant doesn't mean that KS can't kill.  KS can kill, and
 in that way it is quite malignant."
    "The implications of this are important" for treatment of
 Kaposi's sarcoma, he said.  "You might try reversing it,
 rather than killing it with poisonous chemotherapy."  Ongoing
 research may lead to discovery of just such an inhibitor.
    Yet several persistent mysteries surrounding Kaposi's
 sarcoma aren't resolved by the new reports.  Kaposi's sarcoma
 has hit young male homosexuals harder than other groups of
 AIDS patients.  Explanations from herpes virus to recreational
 drugs like amyl nitrates have been considered but largely
 discarded.  Also doctors treating AIDS have observed a recent
 dropoff of Kaposi's sarcoma cases among AIDS patients.

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