 What does breast cancer do with cholesterol? Here are some of the potential mechanisms by which cholesterol boosts breast cancer growth. Cholesterol is what our body makes estrogen out of. It's packaged into LDL, which we saw up here to increase proliferation of breast cancer cells, decrease patient survival, and is a major component of lipid rafts. Compared with their normal counterparts, cancer cells have higher levels of cholesterol-rich lipid rafts in their plasma membranes, which may be important for cancer cell survival, as well as serve in human cancer development, in terms of tumor migration and invasion. Elevated levels of these cholesterol-rich lipid rafts have been found in breast cancer cells, and the thought is that by reducing blood cholesterol levels may disrupt lipid raft formation and thereby inhibit breast cancer development. This suggests cholesterol targeting may be useful as a cancer therapy. Controlled laboratory experiments have shown that phytosterols and seeds and nuts at dietary-relevant levels appeared to inhibit the growth of several types of tumor cells, including breast cancer cells, both estrogen receptor negative and estrogen receptor positive cancer. The therapeutic implications are that plant-based diets, rich in phytosterols, may offer protection against the development of breast cancer. Of course, you can't make a lot of money on pumpkin seeds, so researchers looked at cholesterol-lowering statin drugs. Evaluating the safety of statin drugs for women is particularly difficult, however. Little research has explicitly proceeded from a gender-based perspective. Some petri dish work looked promising, but population studies have shown mixed results. Some studies showed that women on statins had decreased breast cancer risk, some showed increased risk, and most showed no association. But these were all relatively short-term studies. People called long-term statin use was defined as mostly just like three to five years. Breast cancer can take decades to grow. The one study that looked at 10 or more years of statin use only included 62 cases. Given the increase in statin use over the past few decades and the fact that they're commonly prescribed to be taken every day for the rest of your life, the studies published today have had limited ability to evaluate the impact of long durations of use. And we'd better figure this out. About one in four women over 45 in this country are on these drugs. But that was the only data we had until now. Thousands of breast cancer cases included in long-term statin users. Women taking statins for 10 years or more had more than double the risk of both types of breast cancer, invasive ductal carcinoma and invasive lobular carcinoma. Now the number one killer of women is heart disease, not breast cancer. So we still need to bring down cholesterol levels, but might there be a way to get the benefits without the risks? Plant-based diets have been shown to lower LDL cholesterol by over 30% within just a couple weeks, equivalent to most of the standard cholesterol-lowering statin drugs without potential side effects such as increased breast cancer risk.