It's in the Peel - The Protective Hull of These 61 Super Fruits Can Wards Off Cancer: Prunes, Plums, Jujube, Kiwi, Pitaya, Apple, Banana, Lemon, Cherry, Kumquat, Pomelo,...

Peru Ground Cherries could be among the most potent fruity anti-cancer agents nature has to offer.

In all the hoopla around "anti-nutrients", people tend to forget that the majority of the hailed phenols, flavenoids etc. serve the very same purpose, they protect the fruit of certain plants. For a recent study from the School of Public Health and the Chinese Academy of Sciences in Guangzhou, as well as the Peking Univerity Fang Li et al. have now compiled an extensive list of fruits, their peels, pulp and seeds and the corresponding anti-proliferative activity, you may want to use as an anti-cancer shopping guide, when you are grocery shopping... and if you do so, don't peel them: the protective peel is where nature stores most of the stuff that kills cancer cells by having them suffocate in their own reactive oxygen species!

Table 1: Anti lung-, breast-, liver- and colon-cancer activity of 61 fruits,  or rather their pulp, their peel and their seeds; marked in green are all values that are larger than the mean + 60% of the standard devidation (Li. 2013)

I have been thinking for quite some time about the optimal way to present the data, to pick a TOP10 or to come up with a selection and then realized that I - if I were in your position - would like to take a look at the data myself.

Instead of telling you what I thought were the most remarkable results I did thus decide to simply confront you with the complete data marking every value that is at least 60% above the mean + one standard deviation in green and ordering the data by the mean protective effect against the three different cancer types (lung, breast, liver, colon cancer) the researchers have tested for.

If you just take a cursory look at the data, the most striking observation the scientists made is unquestionably, the overall potency of the fruit polyphenols. What you have to keep in mind though is that we are talking about in-vitro studies and direct exposure to dosages of 50.09–141.79 mg/mL, as they were necessary to actually kill breast cancer cells are probably something you will never achieve no matter how many Peru ground cherries you eat. With the latter being among the most potent fruity anti-cancer "meds" we have, it is obvious that the question we will still have to answer pertains to the effects of actually eating any of these items.

It appears out of question that it's not going to hurt you. It should also be obvious that eating a packed of cherries is not going to rid you of existing cancerous growth. On the other hand, there is already plenty of evidence that

• cherries (in this case tart cherries) administered in an extract form, can reduce the risk of colon cancer in rodent models (Kang. 2003)
• polyphenol-rich cloudy apples juices can protect against gastric diseases associated with cancer formation (Graziani. 2005)

etc. The picture that's emerging though is that the in-vivo effects of the above and other fruit polypenols are more or less locally, namely in the gut, where the individual cell is directly exposed to a high amount of the active ingredients in the respective fruit. To achieve maximal benefits and actually battle cancer in other parts of our body than the gut, it may thus be necessary to isolate the molecules, compound them and inject them locally in the the cancerous tissue...

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Bottom line: While consuming high amounts of these anti-cancer fruits will have a plethora of health benefits, which will eventually protect you from cancer in all parts of your body, using them as a druglike medicine in our "war against cancer" would warrant extraction and isolation procedures that allow us to apply them in high concentrations to certain parts of our bodies.
Although I doubt that isolating the nutrients and developing corresponding delivery systems entails insurmountable technical difficulties (in fact corresponding nano-technology would probably be available, already; cf. Khandelia. 2013), I am pretty sure nobody is going to do this; after all, the compounds themselves would not only be non-patentable, because naturally sourced, they would also compromise the sales of conventional cancer drugs and are thus a red rag to any of the big players in the business public health has become.

References:

• Graziani G, D'Argenio G, Tuccillo C, Loguercio C, Ritieni A, Morisco F, Del Vecchio Blanco C, Fogliano V, Romano M. Apple polyphenol extracts prevent damage to human gastric epithelial cells in vitro and to rat gastric mucosa in vivo. Gut. 2005 Feb;54(2):193-200.
• Kang SY, Seeram NP, Nair MG, Bourquin LD. Tart cherry anthocyanins inhibit tumor development in Apc(Min) mice and reduce proliferation of human colon cancer cells. Cancer Lett. 2003 May 8;194(1):13-9.
• Khandelia R, Jaiswal A, Ghosh SS, Chattopadhyay A. Gold Nanoparticle-Protein Agglomerates as Versatile Nanocarriers for Drug Delivery. Small. 2013 Feb 27. 
• Li F, Li S, Li HB, Deng GF, Ling WH, Wu S, Xu XR, Chen F. Antiproliferative activity of peels, pulps and seeds of 61 fruits. Journal of Functional Foods. 20 May 2013.