AACR 102nd Annual Meeting, 2—6 April 2011, Orlando, Florida

Role of adipose tissue in cancer proliferation

Dr Francesco Bertolini – European Institute of Oncology, Milan, Italy

Dr Bertolini, you’ve been giving a talk here on obesity in cancer. There are quite a few things I want to ask you about that because there is, first of all, a link. Can you tell me what is the link, I know there’s an epidemiological link known, but what is known about the science of what is going on between the link of obesity and cancer?

The link has been clear for twenty, or even more, years but so far it has been unclear what are really the players, what is the reason for this link. So far, most of the scientists have been focussing on soluble factors, hormones and so on. Now we have this evidence, along with some other investigators that are promoting this small new field of progenitors present in the adipose tissue, that the white adipose tissue in humans is a very rich reservoir of progenitors. So far, most of the attention about the progenitors has been around the bone marrow, which has been considered so far a unique niche and reservoir for progenitors. We have evidence that the white adipose tissue in men is much richer than the bone marrow as a reservoir of progenitors. These progenitors can go to the cancer, to the neoplasia and promote cancer growth in our observations.

Because progenitor cells have, by definition, a degree of proliferative vigour?

Exactly, and they can become fibroblasts, they can become probably become endothelial cells; they can promote cancer to grow in different ways. Now we are studying, along with other people in Huston and in Columbus, how they promote the cancer growth and what are the single cells that are promoting exactly cancer growth and what are the cells that are less relevant from adipose tissue.

Can you relate your cellular theories and your cellular facts to the epidemiological finding that body mass index, for instance, is related positively to the incidence of cancer?

Yes, we are finding a very good correlation with this body mass index in some parts of the body, particularly the umbilical fat is extremely rich in these progenitors. In fact, there are some correlations that are already finding that the fat in particular areas of a body is particularly detrimental for the risk of developing cancer and having a particularly aggressive type of cancer.

Are you able to distinguish between the types of cancer that could be stimulated by obesity?

Yes, we are focussing on breast cancer and particularly in elderly people it might be that the mammary fat pad is extremely rich in progenitors. So these progenitors can play a local role in promoting the growth of breast cancer.

Now adipose tissue is extremely important because in cosmetic surgery you can use it, you can use it in reconstructive surgery after breast cancer surgery, can you not? Are there implications for transferring adipose tissue from one part of the body to another?

As you correctly pointed out, adipose tissue is used nowadays very intensively, not only for surgical purposes but also to remodel the breast after the surgical removal of cancer. Now our studies and one epidemiological study that has been already accepted for publication made by Professor Petit and Visnu Lohsiriwat in the European Institute of Oncology, is offering evidence that particularly for in situ cancer the lipofilling procedure might be at risk for a higher incidence of local relapse. Of course this should be confirmed in larger studies, but what we will do next, along with surgeons in our institute and scientists, again in Huston and Columbus, Ohio, will be to look at the single cell population that are promoting cancer growth in order to avoid reusing them along with progenitors that are not detrimental for cancer growth.

How hard are the data at the moment, because clinicians do need guidelines? How sure are you about the level of risk of transferring adipose tissue?

I would say that there is no adequate evidence of the lipofilling, lipotransfer procedure being safe or unsafe. It’s a field that should be intensively investigated and it’s the right time to start such an investigation.

You’ve been talking here about this whole issue, what issues would you like to bring to the attention of clinicians then, that they should focus on and remember?

Of course to enrol the patients in controlled clinical trials. This is the only way to be sure that every single patient is offered a variety of information that the scientific community is in need to understand whether or not this procedure is safe. Then the next step will be as soon as possible to investigate what type of cells we are injecting, to be able in the future to tell patients, OK, we are giving you the safe cells and removing the bad cells. That would be a medium term goal but it’s time to start.

And on the issue of body mass index and recommendations to avoid the suspected carcinogenesis, what sort of recommendations, finally, would you make to the general public and to doctors to give their patients about avoiding obesity?

I would say that so far the strongest, and maybe one of very few extremely strong, evidence is that the total intake of food has a correlation with cancer risk. So avoiding eating too much is probably nowadays the safest indication to reduce the body mass index and to reduce the risk of cancer.

And does it rate along with stopping smoking?

Of course, that’s another very risky habit but if you just focus on body mass index, the two things combined together are, for sure, to be avoided.

Francesco, it’s a delight to have you with us today. Thank you for those wise words and for being here with us on ecancer.tv.

Thanks a lot.