ACOG Cuts Down Pap Smear Screening

Women should have their first cervical cancer screening at age 21 and can be re-screened less frequently than previously recommended, according to newly revised evidence-based guidelines issued today by The American College of Obstetricians and Gynecologists (ACOG) and published in the December issue of Obstetrics & Gynecology. Most women younger than 30 should undergo cervical screening once every two years instead of annually, and those age 30 and older can be rescreened once every three years.

ACOG released revised guidelines today following evidence-based research showing less frequent screening prevents cervical cancer just as well as currently recommended annual pap smear test but also cuts down cost and complications (i.e. more premature delivery in female treated with excisional therapies for cervical dysplasia). ACOG also recommended to shift lower age limit for screening to not less than 21 years instead of current guidelines to do screen (and treat dysplais if present) for girls less than 21 years of age and having history of sexual intercourse in for previous 3 or more years.

"Adolescents have most of their childbearing years ahead of them, so it's important to avoid unnecessary procedures that negatively affect the cervix," says Dr. Waxman. "Screening for cervical cancer in adolescents only serves to increase their anxiety and has led to overuse of follow-up procedures for something that usually resolves on its own." 

Also, new recommendations states to discontinue pap test for woman undergone total hysterectomy for non-cancerous conditions or no high-grade cervical intra-epithelial lesions.


Source: Practice Bulletin #109, "Cervical Cytology Screening," is published in the December 2009 issue of Obstetrics & Gynecology. ACOG press release: Nov 20, 2009
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Accelerating Stem cell generation

Hanna, et al. at Rudolf Jaenisch’s lab in MIT have discovered an approach to speed up generation of induced pluripotent cells (iPS), importantly with efficiency rate approaching ~ 100%. Low efficient rate of transformation was one of the biggest obstacle so far in iPS creation. In a news story at nature.com, lab reported to develop a sophisticated system to study reprogramming using genetically  identical mouse immune cells that contain additional copies of four genes (namely, Oct4, Sox2, Klf4 and c-Myc) required for reprogramming. I’ve yet to read details of this system. In brief, using this four genes and their system, they document nearly all cells being transformed to iPS at variable rate of cell division – some transforming early and other at late time-point. Mechanism of variable rate transformation is unclear but this means that all adult cells can be reprogrammed and reprogramming is a continuous dynamic process rather possible cessation after certain time-period in a given cell with those four reprogramming genes. Further, investigating role of oncogenes in iPS, they showed that inhibition of the p53/p21 pathway or over-expression of Lin28 increased the cell division rate and resulted in an accelerated kinetics of iPS cell formation. Interesting to learn, Nanog over-expression transformed cells into iPS at faster rate without significantly affecting cell division, implying cell-division independent mechanisms of reprogramming – yet to be discovered! Team is investigating role of epigenetic events in cell-division dependent and independent models of adult cell reprogramming.

 

Related resources:

1. Abbott A, Faster route to stem-like cells, Nature News 10.1038/news.2009.1070 (8-Nov-2009)

2. Hanna J, et al., Direct cell reprogramming is a stochastic process amenable to acceleration, Nature AOP: 10.1038/nature08592 (8-Nov-2009)

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Bob and his cancer world!

Dr Weinberg presenting annual Albright symposium lecture on Cancer World at Harvard Medical School
Samir

This email is sent via my mobile phone. Please pardon the brevity and any typos.

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Reprogramming The Cell: Part 6 | First live mammalian body from iPS

Nature magazine has just released news about two independent studies in China documenting first successful creation of live mammalian body (mice) from induced pluripotent cells (iPS) derived from mouse fibroblasts. The mouse was named Xiao Xiao or 'Tiny'. Success rate of one team was 1.1% and 3.5% for another. Recent studies showed gene expression signature difference between embryonic stem cells (ESCs) and iPS which means iPS cells behave and act differently than ESCs even though end result is creation of entire mammalian body. This property is important to be taken into account of possible benefits or adverse events associated with iPS use in therapeutic cloning. Ethical concerns would now be more amplified about possible use of iPS in human cloning.
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Further reading: 

1. Nature News: David Cyranoski, Mice made from induced stem cells, Published online 23 July 2009 | Nature | doi:10.1038/460560a

2. Xiao-yang Zhao, et al., iPS cells produce viable mice through tetraploid complementation, Nature advance online publication 23 July 2009 | doi:10.1038/nature08267

3. Kang Lan, et al., iPS Cells Can Support Full-Term Development of Tetraploid Blastocyst-Complemented Embryos, Cell Stem Cell 23 July 2009 | doi:10.1016/j.stem.2009.07.001
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