Excess intake of insulin by diabetics may lead to cancer

Syed Akbar
Hyderabad:  Excess intake of insulin by diabetics may lead to cancer,
says a new study by endocrinologists.
The study, funded by the department of endocrinology and metabolism of
Nizam's Institute of Medical Sciences, pointed out that high levels of
insulin
will decrease the production of insulin growth factor (IGF-1) binding
proteins leading to increased levels of free IGF. This high levels of free
IFG
will have carcinogenic activity in the body and causes cancers.
"We postulate that hyperinsulinaemia which prevails during initial phases of
insulin resistance (condition prior to overt diabetes) increases
bioactivity of
free IGF-1, which may contribute to process of carcinogenesis," point out K
Harish, M Dharmalingam and M Himanshu in their study.
Well controlled studies in humans are essential to study the link between
insulin resistance, hyperinsulinaemia, IGF-1 and carcinogenesis. This study
could provide insights to the role of insulin, insulin resistance, IGF-1 in
carcinogenesis although a precise role and the extent of influence cannot be
determined. In future, cancer prevention and treatment strategies could
revolve around insulin and insulin resistance, they said.
The study suggested that type 2 diabetes might be associated with up to 10 to
20 per cent excess risk for breast cancer and that it could also have
detrimental effects on the natural history, diagnosis, and treatment of
breast
cancer.
"Cancer being a non-communicable disease, with multiple risk factors,
modifiable risk factors are very few. Controlling hyperinsulinaemia would
modify one major risk factor," the study said.
IGF-1 signalling has been highly implicated in development of cancers,
especially epithelial cell cancers. It plays a crucial role in tumour
transformation, malignant cell turn over and survival of cancer cells. Such
roles in normal cell growth are comparatively less.
A pilot study on 63 subjects was conducted as part of the study. A trend
towards significance of association between insulin resistance/sensitivity
and
IGF-1 levels was seen. The trend was stronger in patients below the age of
50. Insulin resistance and associated derangements are largely attributed to
genetic factors. Thus, advanced age could be a confounder for this line of
investigation.