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 * Note: Please use your sandbox to submit assignment # 3 by pasting it below. When uploading your improvements to the article talk page please share your exact proposed edit (not the full assignment 3).


 * Talk Page Template: CARL Medical Editing Initiative/Fall 2019/Talk Page Template

Hereditary Nonpolyposis Colorectal Cancer

Assignment #2
Microsatellite Instability in Lynch Syndrome- Josh Del Papa

1)      Pubmed Search Strategy: "Microsatellite Instability"[All Fields] AND ("Lynch Syndrome"[All Fields] OR "Hereditary nonpolyposis colorectal cancer"[All Fields]) AND Review[ptyp]

2)      Two review articles were identified/considered. The first was titled: “Microsatellite Instability: Diagnosis, Heterogeneity, Discordance, and Clinical Impact in Colorectal Cancer.” And published in Cancers . The second was titled “An updated review of microsatellite instability in the era of next-generation sequencing and precision medicine.” And was published in Seminars in Oncology . The former was chosen for further review.

3)      This review article was chosen over other articles found in the pubmed search due to its accessible language and content that was very specific to the topic in question. It is recently published in a moderate-impact journal, well-written, thorough, and provides excellent references to primary sources on the topic.

4)      #1 This article is a secondary source, i.e. it is a published review article which has curate the evidence from primary sources. #2 it is up to date, having been recently published in October of 2019. #3 It is published in a moderate-impact, well known biomedical journal.

5)      Using this source, the microsatellite instability section of the hereditary nonpolyposis colorectal cancer (HNCC) wiki page will be updated and broadened to include a definition of this phenomenon #1 and a short, succinct explanation of its relevance in HNCC.

Proposed Changes: Addition of two sentences in diagnosis section.
Mutations in DNA mismatch repair systems can lead to difficulty transmitting regions within the DNA which contain repeating patterns of two or three nucleotides (microsatellites), otherwise known as microsatellite instability (MSI). MSI is identified through DNA extraction from both a tumor tissue sample and a normal tissue sample followed by PCR analysis of microsatellite regions. MSI analysis can be used to identify people who may have Lynch syndrome and direct them for further testing.

- The sentences are written in an easy to understand formal, good for non medical people. You also include hyperlinks to other pages for terms that may not be understood. - MSI uses PCR of microsatellite regions in tumour DNA, but DNA is also extracted from non-tumour tissue for comparison. We might want to hyperlink MSI as well as there is a wiki page for this and the reader can go to this for more details. - The end of the 2nd sentence we should probably change as MSI is a screening test and currently may give the impression that is it diagnostic of Lynch. It can be used to identify people who need further testing (ie germline).

Rationale for proposed change:
Microsatellite instability is the important pathogenic mechanism behind lynch syndrome induced cancers, and it can be an important identification modality for this inheritable susceptibility. Briefly describing the phenomenon and the testing mechanism here helps to underline the pathology and the testing capacity in this syndrome.

No ambiguity identified
-One ambiguity with MSI testing is the number of microsatellites tested. There are various panels that can be used.

Critique of Source:
The journal Cancers belongs to the MDPI group of scientific journals, which has come under fire in the past for predatory behaviors, and was briefly included on “Beal’s List” of predatory journals. However, this group was removed from the list and continues to publish high impact papers in a variety of fields. The current impact factor for the Cancers journal is roughly 6.5. This review article is written in an informative way and does not appear to have a particular agenda. The article includes differing opinions and alternate points of view without favoring a particular topic. It is also written in a very accessible manner, especially considering the highly technical nature of this topic.