A study shows that 'mosaicism' is gaining ground in cancer research

June 12, 2012

A study recently published in Nature Genetics provides new evidence that the genetic makeup of the embryo may cause the appearance of tumors in adult life. These results bear out the growing theory that some tumors may have an extremely early origin, tracing to the individual's embryonic development, while offering new clues to understand the genetic causes of certain kinds of cancer, and their prevention and treatment.

Researcher Francisco X. Real, head of the Epithelial Group at the Spanish National Cancer Research Centre (CNIO) took part in the study, which was led by Christian Hafner of the University of Regensburg, Germany.

A cell, when it divides, generates two other identical cells with the same characteristics and . – alterations in the genes – can occur during the embryo's development, and will then be passed to the daughter cells in the division process. The result is an individual whose cells differ genetically. It has long been suspected that this phenomenon, known as mosaicism, could be linked to several types of cancer, but the scientific community has little information on the genetic alterations that underlie it.

The authors of the paper conducted an exhaustive genetic study of 67 patients with a number of congenital skin lesions leading to tumours (nevus sebaceous, NS). They also studied the Schimmelpenning syndrome (SS), in which tissues like the brain or eye are also affected.

Biopsies of these patients' lesions found for the first time mutations in genes of the RAS family (97% in cases of NS and 100% in SS) which encode proteins of key importance in cell division regulation, while analyses of lesion-free tissues, like cells of the mouth mucous, blood leukocytes, etc. found their gene sequence to be normal. Further, all the patients that developed tumours were also mosaic for this gene family.

The above results, and those of previous studies led by the CNIO group, show that these mutations, which are confined solely to the cells of the affected skin and, as congenital conditions, arise during , are the genetic cause of these anomalies and predispose to the formation of tumours.

Analysing the genome of 57,000 people

A complete analysis of the genome of over 57,000 individuals, also published this week in , lends weight to the theory that mosaicism of distant origin is more widely present in patients with tumours than cancer-free individuals.

This second study drew on the combined efforts of 189 researchers worldwide, including Francisco X. Real and fellow CNIO researcher Núria Malats, head of the Genetic and Molecular Epidemiology Group, under the leadership of scientists at the U.S. National Cancer Institute and Pompeu Fabra University in Barcelona.

It is from this variability in the of cells from the same individual that we get the idea of personal genomes, in the plural. "Some of these mutations imply an increased risk of cancer, so certain patients should have more frequent examination to check how their lesions are progressing," explains Real.

Explore further: Children's brain tumors more diverse than previously believed

Related Stories

Children's brain tumors more diverse than previously believed

May 14, 2012
Paediatric brain tumours preserve specific characteristics of the normal cells from which they originate – a previously unknown circumstance with ramifications for how tumour cells respond to treatment. This has been ...

Gene known to protect against cancer can also promote tumor growth: study

March 13, 2012
Can a gene simultaneously protect against cancer and favor its growth? Researchers at the Spanish National Cancer Research Centre have discovered a gene with this double-edged property and suspect there may be many more that ...

Molecular subtypes and genetic alterations may determine response to lung cancer therapy

May 11, 2012
Cancer therapies targeting specific molecular subtypes of the disease allow physicians to tailor treatment to a patient's individual molecular profile. But scientists are finding that in many types of cancer the molecular ...

Mitochondrial genome mutates when reprogrammed

July 28, 2011
Induced pluripotent stem cells (iPS cells) are truly talented multi-taskers. They can reproduce almost all cell types and thus offer great hope in the fight against diseases like Alzheimer's and Parkinson's. However, it would ...

BRG1 mutations confer resistance to hormones in lung cancer

March 15, 2012
Retinoic acid (vitamin A) and steroids are hormones found in our body that protect against oxidative stress, reduce inflammation and are involved in cellular differentiation processes. One of the characteristics of tumours ...

Recommended for you

Study prompts new ideas on cancers' origins

December 16, 2017
Rapidly dividing, yet aberrant stem cells are a major source of cancer. But a new study suggests that mature cells also play a key role in initiating cancer—a finding that could upend the way scientists think about the ...

What does hair loss have to teach us about cancer metastasis?

December 15, 2017
Understanding how cancer cells are able to metastasize—migrate from the primary tumor to distant sites in the body—and developing therapies to inhibit this process are the focus of many laboratories around the country. ...

Cancer immunotherapy may work better in patients with specific genes

December 15, 2017
Cancer cells arise when DNA is mutated, and these cells should be recognized as "foreign" by the immune system. However, cancer cells have found ways to evade detection by the immune system.

Scientists pinpoint gene to blame for poorer survival rate in early-onset breast cancer patients

December 15, 2017
A new study led by scientists at the University of Southampton has found that inherited variation in a particular gene may be to blame for the lower survival rate of patients diagnosed with early-onset breast cancer.

Scientists unlock structure of mTOR, a key cancer cell signaling protein

December 14, 2017
Researchers in the Sloan Kettering Institute have solved the structure of an important signaling molecule in cancer cells. They used a new technology called cryo-EM to visualize the structure in three dimensions. The detailed ...

'Bet hedging' explains the efficacy of many combination cancer therapies

December 14, 2017
The efficacy of many FDA-approved cancer drug combinations is not due to synergistic interactions between drugs, but rather to a form of "bet hedging," according to a new study published by Harvard Medical School researchers ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.