The Obesity - Cancer Connection

A team of researchers from Tulane University published a very intriguing report in the February 2015 issue of Stem Cells that focuses on the manner in which stem cells directly influence obesity-associated cancers.

These findings have profound effects in our understanding of adipose (fat) cells, adipose stem cells (ASC's), and cancer cells specifically related to obesity.  The interplay between these is not only fascinating, but also may lead to future treatments for a variety of these types of cancer.

This study is especially important at a time when the obesity rates globally continue to increase. It is estimated that one third of American adults are obese, meaning over 80 million people in this country alone.  The World Cancer Research Fund used meta-analysis research in 2007 to study the effects of obesity on incidence of cancer and the associated mortality.  They found that as fat levels increase, so do the rates of colorectal, renal, and postmenopausal breast carcinomas.  See the website at  http://www.wcrf.org/int/cancer-facts-figures/link-between-lifestyle-cancer-risk/cancers-linked-greater-body-fatness.  A number of other studies have also shown increases in cancer among obese patients - this includes prostate, endometrial, liver, ovarian, and esophageal cancers, along with hematological malignancies, and certain lymphomas and melanomas.

Here are some more links in regards to specific cancers:
General obesity - http://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(02)00849-5/abstract?cc=y ; http://www.ncbi.nlm.nih.gov/pubmed/19824817
Prostate cancer - http://www.ncbi.nlm.nih.gov/pubmed/17507151
Endometrial cancer - http://onlinelibrary.wiley.com/doi/10.1111/1471-0528.12106/abstract ;
                                   http://www.hindawi.com/journals/ogi/2011/308609/
Liver cancer - http://www.ncbi.nlm.nih.gov/pubmed/15508109
Ovarian cancer - http://www.ncbi.nlm.nih.gov/pubmed/23402904

This is only a very small amount of data in regards to this topic, as a complete list of the studies is too numerous to provide here.

This previous research found a link between obesity and certain cancers, yet the actual causal mechanism had not been found.  The just-published study suggests that stem cells are altered by obesity and integrate into the tumors themselves, providing support for tumor growth. Genes from ASC's in obese patients are expressed differently from those in normal wight individuals, and the data gathered tends to imply that the ASC's from obese patients have an increased propensity to assist cancer cells and further their survival.  The number of stem cells in circulation was significantly greater in obese patients, even further increasing the likelihood of these ASC's having the opportunity to migrate to the tumor site and encourage further cancer growth.  And finally, the ASC's from the obese population expressed a greater amount of certain chemical factors that aid cancer cell proliferation and even migration/metastasis.

These findings are just the beginning in terms of research on obesity-linked cancers.  Future investigation will focus on how obesity changes our stem cells and predisposes to an increased incidence of cancer, and will also hopefully lead to information that might help eventually reduce cancer risk.  Also, as growing research is showing, there will be ways to use stem cells to fight various cancers, by changing how the stem cells work and making them actually inhibit growth and even destroy cancer cells.