Many factors determine a person's risk of having cancer, among them lifestyle factors such as diet and exercise, genetics and environmental influences.
Dr Wael Abdel-Rahman, an associate professor in the College of Health Sciences at the University of Sharjah, has long been keen to better understand the environmental effects and how they could be causing some people to contract cancer.
It is an interest that started early in his career when he worked in Egypt as a histopathologist, a doctor who examines tissue samples, usually under the microscope, to identify disease.
He was struck by the many cases he came across of colon cancer, breast cancer and hepatocellular carcinoma (a type of liver cancer), often in people aged 50 or younger.
These diseases were often diagnosed at an advanced stage and therefore tended to have a poor prognosis.
Such diagnoses were seen less often in the West – which Dr Abdel-Rahman observed when he worked in Britain and Finland – and he was keen to find out what was causing these differences.
“Many clinicians working in the Middle Eastern countries realise this and simply accept these as known ethnic variations,” he said.
Another explanation is that chemicals in the environment could be partly responsible.
To help indicate whether this could be the case, Dr Abdel-Rahman and a team of researchers have, for the past year and a half, been looking at the effects that various chemicals found in the environment have on human cell lines.
Funded by the Al Jalila Foundation, the work involves testing chemicals such as bisphenol A (BPA), an artificially made organic compound found in some plastics. Also on the list of substances being tested is nonylphenol, which has been used in some detergents.
The substances are known as endocrine disruptors because they affect the body’s endocrine system, a network of glands that produce hormones regulating various body functions.
The chemicals have been tested on mammary epithelial cells (cells from the epithelium or lining of the breast milk ducts), breast cancer cells, colon epithelial cells and colon cancer cells. The cells were exposed to the chemicals for up to two months, longer than usual in this type of research.
The study is ongoing and the results are preliminary, but the researchers have already identified various effects. In particular, the chemicals seem to make the cancer cells more robust in staying alive, and make the breast cancer and the colon cancer cells more resistant to anti-cancer agents.
“There have been some changes in the cellular abilities to form colonies but this is still an ongoing experiment,” said Dr Abdel-Rahman.
“Our findings might add evidence to support the hazardous effect of some of these toxic chemicals.”
Some of the effects of the chemicals could be linked to changes in the levels of “methylation” of genes.
A methyl group is a chemical group of one carbon atom linked to three hydrogen atoms.
Changes in the pattern of methylation of genes – the groups are attached directly to the DNA – do not change the composition of the proteins that genes code for.
However, methylation alters how active genes are and the extent to which they are expressed, and this can influence whether or not tissues go on to develop tumours.
Cancerous tissue has been found to have increased variability in the methylation of its DNA.
In an earlier research project, Dr Abdel-Rahman collected colon cancer samples from Egypt and compared them with similar samples from Finland.
In results published in 2012 in the journal Cancer Epidemiology, Biomarkers and Prevention, the Egyptian cancers tested by Dr Abdel-Rahman and his fellow researchers were found to have higher levels of methylation in the promoter region (stretches of DNA that influence how active genes are) of tumour-suppressor genes (genes that can prevent cells from becoming cancerous).
This study also suggested a possible link between methylation and environmental exposure to carcinogens.
“This prompted me to propose the current project to analyse the various effects of common environmental toxins in cellular viability and behaviour,” said Dr Abdel-Rahman.
The Al Jalila Foundation has supported the project through a two-year grant that began about 18 months ago. The project involves Dr Abdel-Rahman as the main investigator, Dr Aravind S R, a postdoctoral researcher, and Vidhya A N, a technician. Dr Abdel-Rahman runs a group of 10 researchers in all – the Cancer and Environment Research Group, which is part of the Sharjah Institute for Medical Research.
Also involved in the latest study is Prof Paivi Peltomaki and her researchers at the University of Helsinki in Finland.
Last month, at the 9th Dubai International Conference for Medical Sciences, Dr Abdel-Rahman was awarded the Sheikh Hamdan Bin Rashid Al Maktoum Award for Medical Sciences for his research.
The researchers have been looking for many different types of changes in the cell lines. As well as analysing how viable the cells are and the extent to which exposure to toxins causes the cells to die or makes the cells resistant to anti-cancer agents, the researchers have measured the cells’ ability to proliferate, to be mobile and to be invasive.
They are also looking at whether the chemicals cause DNA damage and, in an echo of the study published in 2012, at the levels of methylation of gene promoters of tumour-suppressor genes.
“The effect on different cells lines is something new in this study. For example, BPA and most of the endocrine disruptors are known to be associated with the risk of breast cancer but there are very few studies addressing their effect and relationship with colon cancer, even though these enter the body, usually by ingestion,” said Dr Abdel-Rahman.
The Sharjah researchers have further analysis of cell behaviour to complete, and their partners in Finland have also yet to complete their work. The aim is to publish the findings in a major scientific journal.
The results are eagerly awaited because they could reveal more about the causes of the high rates of cancer among young people that Dr Abdel-Rahman saw early in his career and offer clues as to whether factors such as chemicals in the environment might be responsible.