New Biomarker Discovered That May Detect Breast Cancer (dateline November 30, 1999)
A research group at Louisiana State University has discovered a biomarker that may eventually allow health care providers to screen for breast cancer by drawing and testing a patient’s blood. The group, led by Prakash Rao, PhD, studied 102 women; 52 of the women had breast cancer and 50 had either leukemia, no cancer, or fibrocystic change (a non-cancerous condition). The results of the study revealed that 90% of the women with breast cancer had increased levels of the riboflavin carrier protein (RCP) in their blood. RCP is a protein that carries the nutrient riboflavin to cells, helping them to grow and multiply.
The term, biomarker (also called tumor marker), refers to a substance found in an increased amount in the blood, other body fluids, or tissues that may suggest the presence of some type of cancer. The researchers also found that the amount of RCP found in the blood correlates to a woman’s stage of breast cancer. Women with higher levels of RCP had more advanced stages of breast cancer. Additionally, women with the highest levels of RCP in their blood were found to have estrogen receptor-positive (ER-positive) tumors. ER-positive tumors depend on the female hormone estrogen for survival and reproduction.
Though the study is promising, researchers are quick to point out that the results need further confirmation. 12% of the women tested had false-positive results: the biomarker was detected in these women even though they did not have cancer. Even with less than perfect results, Dr. Rao and the researchers believe that testing for RCP levels may eventually become valuable when used in conjunction with other tests for breast cancer. Currently, women at high breast cancer risk may be tested for the presence of a mutated BRCA1 (Breast Cancer Gene 1) and BRCA2 (Breast Cancer Gene 2), the mutated p53 tumor suppressor , or increased amounts of the hormone receptor, HER2.
The discovery of the RCP biomarker may help health care providers detect breast cancer at an early stage. In general, the earlier breast cancer is discovered, the better the patient’s prognosis (projected outcome). Ductal carcinoma in situ , a Stage 0 cancer, is virtually 100% curable if the cancer is treated while it is confined to the milk ducts in the breast and has not spread into the fatty breast tissue or to any other part of the body (such as the lymph nodes).
The American Cancer Society has recommended a set of guidelines women should follow to help detect breast cancer at an early stage:
- Women 20 years of age and older should practice monthly breast self-examination (BSE).
- Women between 20 and 39 years of age should have a clinical breast exam (CBE) at least every three years in addition to practicing monthly BSE.
- Women 40 years of age and older should have a yearly screening mammogram in addition to a yearly CBE and monthly BSE.
- Women with a high risk of breast cancer and/or family history of breast cancer are
encouraged to consult their doctor or other trained medical professional about receiving
annual screening mammograms starting between the ages of 30 and 40. Woman at a very high
risk of breast cancer (such as those tested positive for the BRCA1 and BRCA2 breast cancer
genes) should speak with their physician about beginning annual mammograms as early as age
The RCP biomarker is an important discovery for women at high risk of developing breast cancer since these women may become candidates for RCP testing. Risk factors of breast cancer include:
- Family history
- Previous breast biopsy
- showing benign conditions
- Menstruation beginning at an early age
- Menstruation continuing past age 50
- Not having children
- Having a first child after age 30
- High fat diets
- Mutations of the genes, BRCA1 and BRCA2
In addition to the new breast cancer biomarker, researchers have previously discovered the CA125 biomarker for ovarian cancer , the CA 19-9 biomarker for colon cancer, the CEA biomarker for ovarian, lung, pancreas, and gastrointestinal cancers, and the PSA biomarker for prostate cancer. The CA 15-3 biomarker may also indicate breast cancer. CA 15-3 measures the levels of glycoprotein, a protein which is shed from breast cancer tumor cells into the bloodstream.
- The American Society of Clinical Oncology provides information on "Clinical Practice Guidelines for the Use of Tumor Markers in Breast and Colorectal Cancer" available at http://www.asco.org/prof/pp/html/m_tumor1.asp
- The November 11, 1999 News Today report, "New Biomarker in Blood May Help Detect Breast Cancer," is available http://www2.cancer.org/zine/dsp_StoryIndex.cfm?sc=001&fn=001_11111999_0
- To learn more about the genetic risk factors for breast cancer, please visit http://www.imaginis.com/breasthealth/genetic_risks.asp.
- To learn more about guidelines for the early detection of breast cancer, please visit http://www.imaginis.com/breasthealth/earlydetection.asp