More and more media reports are mentioning the potential merits of marijuana. The most recent headlines say the active ingredient in the drug cuts tumor growth in common lung cancers in half and greatly reduces the ability of the cancer to spread.

Researchers at Harvard University tested marijuana's main ingredient, delta-tetrahydrocannabinol or THC, in both lab and mouse studies and say their experiments are the first to show THC inhibits the growth of cancer.

Researchers are not certain why THC inhibits tumor growth, but it could be that the substance activates molecules that arrest the cell cycle. THC may also interfere with angiogenesis and vascularization, which promotes cancer growth.

There is a long way to go in the study of THC. Yet "the beauty of this study is that we are showing that a substance of abuse, if used prudently, may offer a new road to therapy against lung cancer," says Anju Preet, Ph.D., a researcher in the Division of Experimental Medicine.

If you have ever been diagnosed with breast cancer, it is quite likely that one of the first books, if not the only book, recommended to you was Dr. Susan Love's Breast Book. The New York Times rightly refers to her book as "the bible for women with breast cancer." Her second book, Dr. Susan Love's Menopause and Hormone Book, was one of the first to question the widespread use of postmenopausal hormones. Dr. Love is a genuinely trusted presence and clear voice in the world of women's breast health.

An eminent pioneer in the field of breast cancer for 30 years, and considered one of the founding mothers of the breast cancer advocacy movement, her mission, and the mission of the Dr. Susan Love Research Foundation, is to eradicate breast cancer within our lifetime and better the lives of women by generating resources and innovation for education, research, and advocacy on women's health issues.

Part of the recently redesigned Dr. Susan Love Research Foundation website is the addition of a blog. Dr. Love is blogging the San Antonio for the San Antonio Breast Cancer Symposium where she joins more than 8000 physicians, scientists, and breast cancer advocates in what is considered one of the most important conferences held each year regarding cancer.

On the first day, Dr. Love blogs both clinical and big picture highlights, including her take on two newsworthy study findings we posted here earlier today. The first concerns the common house mouse virus link to breast cancer and the second one regarding the dramatic decrease in breast cancer cases and the corresponding decrease in women using hormone replacement therapy (HRT).

Dr. Love posted, "There was a sudden dramatic (7 percent) decrease in breast cancer in 2003 corresponding with the equally dramatic decrease in women who stopped taking HRT after the WHI study found it appeared to do more harm than good. The study found 14,000 less breast cancers in one year! In my mind this is the final proof we need that taking hormonal therapy after menopause for the prevention of the diseases of aging makes no sense."

For a trusted analysis of the conference, you can find Dr. Love blogging the San Antonio Breast Cancer Symposium here.

A variation of a virus that infects common household mice might be responsible for one-third of the breast cancer cases occurring in the US, according to research presented at the San Antonio Breast Cancer Symposium as reported by WedMD.

The mouse mammary tumor virus (MMTV), is spread like a cold virus from person to person, although the researchers are not certain if this virus is spread by sneezing or food contamination, or other means of transmission.

Mt. Sinai School of Medicine's Dr. James F. Holland is quoted as saying, "In Asia, the virus plays a very small role in causing the disease. The human breast cancer virus may explain why breast cancer rates differ throughout the world." The house mouse in question is not commonly found in Asia.

For so long, we have been told that the Asian diet pyramid, when compared to the Western diet pyramid, was one of the contributing factors in higher breast cancer cases for US women, and lower breast cancer cases for Asian women. It might well bea contributing factor still, as diet is firmly established as a cause for increasing the risks of all cancers. However, we cannot ignore that the researchers found the common house mouse virus present in the breast cancer tissue samples in 30-40 percent of the women from North America, Europe, and Australia.

That virus plays a role in the development of some cancers is a known, and it brings up interesting questions as to what leads to cancer, and potentially some explanations for the incidence of breast cancer for women who practice what is traditionally considered a healthy lifestyle and have none of the risk factors. Cancer is complex. As time goes on, I believe we are all going to sit back and be surprised at some of the causes for cancer as they are discovered.