Like apples, pears (Pyrus communis) are a member of the Rosaceae family. Pears are a good source of dietary fiber, and ursolic acid. Pears also contain some chlorogenic acid, oleanolic acid, phloretin, vitamin C and vitamin K. While these compounds are beneficial, pears have low chemopreventive activities compared to many other fruits.
Most of the beneficial compounds found in pears are concentrated in the skins. Pears may reduce the risk of stroke and have cholesterol-lowering activities, in addition to improving insulin resistance.

Cancer-related effects of eating pears

Consumption of pears has been found to be associated with lower risks head and neck, esophageal, lung, gastric and colorectal cancer in epidemiological studies. One small Swiss population study found that consumption of pears was associated with lower risk of breast cancer. However, pears contain only modest levels of micronutrients that have been linked to lower breast cancer risk compared to apples and many other fruits.

Ursolic acid

Ursolic acid, which is found in pear peels, has been shown to reverse multidrug resistance in breast cancer cells. One study found that ursolic acid reversed resistance to Taxol in Taxol-resistant triple negative breast cancer. Another study reported that ursolic acid resensitized multidrug resistant ER+/PR+ breast cancer cells to Adriamycin. Still another study reported that ursolic acid increased the sensitivity of triple negative breast cancer cells to Adriamycin.

Additional comments

As noted above, pear skins contain far more biologically active compounds than the flesh. However, non-organic pears must be washed very thoroughly to remove pesticide residue as much as possible.
Prickly pears or cactus pears are a type of cactus unrelated to pears.
Below are links to recent studies concerning this food and its components. For a more complete list of studies, please click on pear.