Wednesday, November 29, 2017

MORE ON PARP


Double stranded break in DNA, on the right
PARP will fix it, unless we intervene

Here is an update on PARP inhibitors as applied to ovarian cancer.  I have been guilty of runaway enthusiasm for immunotherapy; until immunotherapy proves to be the weapon that eventually eliminates ovarian cancer (as I believe), PARP inhibitor drugs will serve the vital purpose of extending lives.  This article speaks of PFS (progression-free survival) rather than mortality, but surely the two must roughly  correlate.  The article describes several clinical trials, which found that the PARP drugs in general lengthened PFS by one to two years.  In the past I have been scornful of treatments that were not outright cures,  but now I realize I was wrong.  What would I not have given or done to give Linda an extra 18 months  of life?

This article is tough sledding in places, so you should glance at the following glossary before you try:

PARP (Poly ADP ribose polymerase) is a family of proteins that serve to repair double-stranded DNA breaks.  OVCA cancer cells have many such breaks, so if you can screw up the PARP you can inhibit growth of the cancer.

Germline BRCA mutations refers to inherited DNA defects.

Platinum-based, platinum-sensitive:  Most standard OVCA chemo drugs are based on platinum, which most OVCA cancer cells don’t like at all.  Unfortunately, some such cells almost inevitably survive – leading to recurrence.

AE:  Adverse effects, meaning bad side effects

Neutropenia means a deficiency of certain essential white blood cells

Thrombocytopenia seems to be a difficult way to say platlet-deficiency

BRCA “wild type” means unmutated BRCA genes.  For some reason geneticists refer to an undamaged chunk of DNA as “wild”.  They must lead an awfully placid life.

Okay, now give this a try.


And for trying, here is an award:



Linda and my Mom, probably 1982



5 comments:

  1. OncLive is a consistently useful source of cancer news. Here is a little squib on the use of PARP inhibitors to combat ovarian cancer. Not much biology, but lots of encouragement.

    http://www.onclive.com/insights/parp-inhibitors-ovarian/the-future-role-of-parp-inhibition-in-ovarian-cancer

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  2. Wheels within wheels. It appears that having undergone previous chemo lessens the effectiveness of PARP inhibitor treatment. View the video – and imagine having this guy as your major professor.

    https://www.onclive.com/onclive-tv/dr-konecny-on-resistance-to-parp-inhibitors-in-ovarian-cancer

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  3. Good Lord! Nothing is ever simple in the onc research world, it seems. Here is a new development "clarifying" why some BRCA-motivated breast and ovarian cancers don't respond to PARP inhibitors. Read it, then explain it to me.

    https://www.rockefeller.edu/news/23193-scientists-discover-mechanism-drug-resistance-breast-ovarian-cancer/

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  4. This may be a bit too specialized for the likes of us, but if you have OVCA let us hope that your oncologist knows this stuff:

    https://www.onclive.com/onclive-tv/dr-campos-discusses-differences-between-parp-inhibitors-in-recurrent-ovarian-cancer

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  5. And they stumble forward, I guess

    https://www.onclive.com/web-exclusives/parp-inhibition-moves-to-next-phase-in-ovarian-cancer

    ReplyDelete