Saliva and the Pancreas
The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, and somatostatin, as well as an exocrine gland, secreting pancreatic juice containing digestive enzymes that pass to the small intestine. There may soon be a new weapon in the battle against the so-called "worst" cancer - cancer of the pancreas. A multidisciplinary group of investigators from the UCLA School of Dentistry, the David Geffen School of Medicine at UCLA, the UCLA School of Public Health and UCLA's Jonsson Comprehensive Cancer Center has demonstrated the usefulness of salivary diagnostics in the effort to find and fight the disease.
Pancreatic ductal adenocarcinoma, the most common type of cancer of the pancreas, is also the most lethal of all cancers, with a mortality rate that is approximately the same as the rate of incidence. The American Cancer Society reports that more than 42,000 people in the United States received a diagnosis of pancreatic cancer in 2009, and the disease caused more than 35,000 deaths.
Pancreatic cancer is the fourth leading cause of cancer death in this country. For both men and women, the lifetime risk of developing pancreatic cancer is about one in 72.
Potential risk factors for pancreatic cancer include:
* Age (particularly over 60)
* Male sex
* African-American ethnicity
* Diets low in vegetables and fruits
* Diets high in red meat
* Family history,
* Gingivitis or periodontal disease
Pancreatic cancer has symptoms of abdominal pain and jaundice but only in the advanced stage of the disease, making it difficult to find in its early stages. Fewer than 5 percent of those diagnosed with the disease live for five years, and full remission is very rare, according to the World Health Organization.
"Worldwide, the prevalence of pancreatic cancer is so high, and the disease is so deadly, that it calls out for a reliable means of early diagnosis," said the study's senior investigator, Dr. David Wong, D.M.D., D.M.Sc., UCLA's Felix and Mildred Yip Professor of Dentistry and associate dean of research at the dental school.
In the past few years, technological advances have pushed the concept of salivary diagnostics for systemic disease to the forefront of scientific attention.
"David Wong and his team at the dental school have demonstrated the usefulness of saliva in detecting oral cancer," said co-first author Dr. James Farrell, M.D., an associate professor in the UCLA Division of Digestive Diseases and director of the Pancreatic Diseases Program at UCLA. "As a clinician-scientist who manages patients with all stages of pancreatic cancer, I was eager to work with them to explore the possibilities it could yield in diagnosing this disease."
In the study, the researchers successfully linked changes in the molecular signatures found in human saliva to the presence of early stage pancreatic cancer.
By analyzing altered gene expression, the researchers identified four messenger RNA (mRNA) biomarkers - KRAS, MBD3L2, ACRV1 and DPM1 - that differentiate pancreatic cancer patients from non-cancer subjects (both those diagnosed with chronic pancreatitis and healthy controls) with 90 percent sensitivity and 95 percent specificity.
"Not only are these saliva based diagnostic methods for pancreatic cancer simple and noninvasive, they may also represent an improvement in specificity and sensitivity over currently used procedures, such as blood tests, for early pancreatic cancer detection," Farrell said.
Due to the study's modest sample size of 90 human subjects, the researchers acknowledge limitations, yet express enthusiasm for further research. They are formulating plans to test the salivary biomarkers in a larger population in a multicenter study. They note that the potential for salivary mRNA biomarkers to identify very early stage and even pre-invasive pancreatic cancer requires further investigation.
For further information: http://www.ucop.edu/sciencetoday/article/22883