About Careers MedBlog Contact us

DNA Structures Called Microsatellites Linked to Cancer Progression, Survival

by Dr. Trupti Shirole on October 5, 2016 at 10:30 PM
Font : A-A+

 DNA Structures Called Microsatellites Linked to Cancer Progression, Survival

Microsatellites are short stretches in our genomes made up of repetitive sequences of DNA, the molecules that code genetic instructions. These microsatellites are typically made of units composed of two to five DNA building blocks, called nucleotides, that repeat between five to 50 times.

These microsatellites may play a far greater role in the development and progression of cancer than previously thought, UW Medicine researchers report in a study appearing in the journal Nature Medicine.


"These findings give us new insights into the basic biology of cancer and open opportunities for new ways to type and potentially treat a wide variety of cancers," said senior author Stephen J Salipante, University of Washington assistant professor of laboratory medicine.

For example, a microsatellite might be composed of five repeats of the nucleotides thymine, designated by the letter T, and adenine, designated A, and read "TATATATATA." Because of these repetitions, the enzymes which copy DNA may accidentally add or subtract nucleotides from them.

As a result, microsatellite sites often mutate relatively quickly. They grow longer and shorter over time. In some cancers, these sites become even more prone to mutations, often because of faulty DNA repair mechanisms. The result is a condition called "microsatellite instability."

Our genomes have hundreds of thousands of microsatellites, but most are in areas where mutations, if they occur, seem to have no effect on cell growth, development and function. However, microsatellite mutations that occur near or within genes or in areas of the genome that regulate gene expression can have a biological effect.

A number of these appear to play a role in gastric, colorectal, and endometrial cancers.

Previous research has mainly looked at relatively few microsatellites in just a handful of cancers types with the microsatellite instability condition.

In the latest published study, Salipante worked with collaborators Ronald Hause and Jay Shendure, both in the UW Department of Genome Sciences, and Colin Pritchard in the UW Department of Laboratory Medicine.

The team used a new technique to analyze sequences of all the genes from nearly 6,000 tumors from 18 different kinds of cancer. The researchers obtained the sequencing information from a massive genome database storehouse called The Cancer Genome Atlas. Their technique and the availability of this atlas allowed them to examine more than 200,000 microsatellite sites in many different cancer types.

They found that most cancer types had examples of tumors with microsatellite instability. They also learned that different cancer types had distinct patterns of mutation across their microsatellites.

Over half of the microsatellite instability sites they uncovered were within or near so-called "cancer genes" - genes that that are implicated in cancer development and progression.

This finding suggests the microsatellite mutations may be causing these genes to malfunction.

The other half of the microsatellite instability sites were not located in or near known cancer genes, but because these mutations were frequent among the different tumor types, they could possibly play a yet undetermined role in cancer.

"These sites may be pointing to new cancer genes that we haven't previously known about," Salipante said.

The researchers also observed a paradox: patients who had tumors with comparatively more unstable microsatellite sites tended to survive longer.

Salipante and his colleagues hypothesize that cancers cells with relatively high numbers of microsatellite instability events are producing more mutated proteins of all kinds, not just cancer genes. These mutated proteins draw the attention of the immune system and trigger immune attacks that slow tumor progression.

"This suggests that by analyzing the entire genome of a tumor instead of just a few microsatellite sites as is done now, it will be possible to identify those patients with tumors that will most likely to respond to new cancer immunotherapies," Salipante said.

Source: Newswise

News A-Z
What's New on Medindia
Diet and Oral Health: The Sugary Connection May Become Sour
World AIDS Day 2022 - Equalize!
Test Your Knowledge on Sugar Intake and Oral Health
View all
Recommended Reading
News Archive
News Category

Medindia Newsletters Subscribe to our Free Newsletters!
Terms & Conditions and Privacy Policy.

More News on:
DNA Finger Printing Cancer and Homeopathy Cancer Facts Genetic Testing of Diseases Cancer Tattoos A Body Art Epigenetics Common Lifestyle Habits that Cause Diseases Health Benefits of Dandelion Plant Oxidative Stress / Free Radicals Cell Injury 

Most Popular on Medindia

Nutam (400mg) (Piracetam) Vent Forte (Theophylline) Color Blindness Calculator Pregnancy Confirmation Calculator Calculate Ideal Weight for Infants Iron Intake Calculator Find a Hospital The Essence of Yoga Post-Nasal Drip Drug - Food Interactions
This site uses cookies to deliver our services.By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Use  Ok, Got it. Close

DNA Structures Called Microsatellites Linked to Cancer Progression, Survival Personalised Printable Document (PDF)

Please complete this form and we'll send you a personalised information that is requested

You may use this for your own reference or forward it to your friends.

Please use the information prudently. If you are not a medical doctor please remember to consult your healthcare provider as this information is not a substitute for professional advice.

Name *

Email Address *

Country *

Areas of Interests