It was known that people with AIDS had a greater risk for HPV-associated cancers of the anus, cervix, penis, vagina, vulva and oropharynx. However, the extent to which AIDS-related weakening of the immune system played a role wasn’t clear, the researchers pointed out.

For this study, researchers at the U.S. National Cancer Institute analyzed cancer registry data on almost 500,000 people diagnosed with AIDS between 1980 and 2004. They found that people with AIDS had a statistically significant higher risk for all HPV-related cancers.

“Given that individuals currently infected with HIV may obtain little benefit from available HPV vaccines…our results underscore the need for effective screening for cervical cancer and anal cancer among persons with HIV infections or AIDS,” the researchers wrote.

The study was published online July 31 in the Journal of the National Cancer Institute.

While it does offer new evidence of the link between HIV/AIDS and HPV-related cancer, the study doesn’t actually prove a biological connection, Dr. Howard D. Strickler, of the Department of Epidemiology and Population Health at Albert Einstein College of Medicine, wrote in an accompanying editorial.

Basal breast cancers account for 20 percent of all breast cancers and are among the most aggressive. They occur in women carrying mutations of the tumor-suppressing gene BRCA1 and have long been thought to originate in breast stem cells.

However, a research team led by Jane Visvader and Geoff Lindeman from The Walter and Eliza Hall Institute of Medical Research in Australia has found that the real culprits may instead be pre-cancerous cells lining the mammary ducts.

The finding opens the way for developing new drugs or therapies to treat this form of breast cancer, Lindeman said.

“BRCA1 women have approximately a 65 percent lifetime chance of developing breast cancer. Following surgery, treatment options available to these women are often limited to chemotherapy and radiotherapy, so identifying new treatment and prevention strategies is a priority for us,” he said in a statement.

Breast cancer is the most common type of cancer among women and one of the leading causes of their premature death.

In the study, the researchers compared normal, non-cancerous breast tissues taken from BRCA1 mutation carriers, women not carrying the mutant gene, and women without the mutant gene but who had a positive family history of the disease.

Tissues from women with the mutant gene had high numbers of pre-cancerous cells lining the mammary ducts, they found.

These pre-cancerous cells were also genetically more similar to basal breast tumor cells, they wrote in their paper, which was published in Nature Medicine.

“They are clearly abnormal cells as they have aberrant growth properties and the population is enlarged in BRCA1 mutation carriers,” said Visvader in an email to Reuters.

One way to prevent this cancer was to target these pre-cancerous mammary duct cells, she added.

“Our gene profiling studies have revealed genes that could serve as possible tumor markers that can be used in breast cancer diagnosis — and has helped to identify possible therapeutic targets to treat (and possibly prevent) basal breast tumors,” Visvader said.

Future work in this area is likely to help the next generation of women.”

In the study, the researchers discovered that genetic variation in a region of chromosome 9 that contains the gene for ABO blood type was associated with pancreatic cancer risk. Individuals with the variant that results in blood types A, B, or AB were at an increased risk of pancreatic cancer, compared to those with the variant for blood type O. This finding is consistent with previous research, some of it dating back to the 1950s and 1960s, that had shown increased risks of gastric and pancreatic cancer among individuals of the A and B blood groups (i.e., blood types A, B, and AB). The latest results provide a genetic basis for those earlier observations.

A person’s blood type depends on which form or forms of the ABO gene they inherit from their parents. The protein produced by the ABO gene determines the type of carbohydrates (complex sugars) that are present on the surface of red blood cells and other cells, including cells of the pancreas. The proteins encoded by the A and B forms of the gene transfer different carbohydrates onto the cell surfaces to make A and B blood types. The O form encodes a protein that is unable to transfer carbohydrates. Studies by other researchers have shown that ABO protein encoding in pancreatic tumor cells is different than in normal pancreatic cells.

To discover genetic variations that contribute to pancreatic cancer risk, the research team conducted a genome-wide association study (GWAS). In a GWAS, researchers analyze common variants, called single-nucleotide polymorphisms (SNPs), in the genomes of people with a disease and people without the disease. Initially, the research team studied the genomes of 1,896 patients with pancreatic cancer and 1,939 control subjects to identify SNPs with a strong association with pancreatic cancer. The team then verified its findings by studying the genomes of another 2,457 people with pancreatic cancer and 2,654 people without the disease. In the end, they identified several SNPs on the long arm of chromosome 9 that were associated with pancreatic cancer risk and mapped to the ABO gene.

“Only by working across disciplines and with more than a dozen research groups were we able to make this important discovery of the potential role of the ABO gene in pancreatic cancer risk,” said co-author Patricia Hartge, Sc.D., of NCI’s Division of Cancer Epidemiology and Genetics (DCEG). “Although it will take much more work, this finding may lead to improved diagnostic and therapeutic interventions that are so desperately needed.”

Pancreatic cancer is the fourth leading cause of cancer death in the United States. It is difficult to detect, and in many people it is not diagnosed until after the disease has spread to other parts of the body. Less than five percent of Americans with pancreatic cancer survive five years past diagnosis. Risk factors include smoking, diabetes, race, and a family history of the disease.

“Pancreatic cancer is the newest beneficiary of so-called high-throughput genotyping that, over the past two years, has yielded scores of genetic hot-spots linked to risk for cancer and other diseases,” said co-author Stephen J. Chanock, M.D., chief of NCI’s Laboratory of Translational Genomics in DCEG. “As more variants are discovered and follow-up studies are conducted to examine the biological effects of these variants, a better understanding will emerge of the inherited risk factors and mechanisms that lead to the development of pancreatic cancer.”

The study was part of PanScan, a GWAS of pancreatic cancer conducted by the Pancreatic Cancer Cohort Consortium, composed of 14 academic centers. The investigators are conducting whole-genome scans to identify common genetic variants that may be markers of susceptibility to pancreatic cancer.

Analyses and data from PanScan will be available through NCI’s caBIG (Cancer Biomedical Informatics Grid). The summary results for similar data on breast and prostate cancer are already freely available to other researchers at this Web site.

For more information on Dr. Hartge’s research, please go to http://dceg.cancer.gov/about/staff-bios/hartge-patricia.

For more information on Dr. Chanock’s research, please go to http://dceg.cancer.gov/about/staff-bios/chanock-stephen.