Researchers Link Low Levels of Pro-Enkephalin to Future Breast Cancer in Healthy Women

In In The News by Barbara Jacoby


sphingotec LLC ( announced today that the results of two studies examining the association between proenkephalin (pro-ENK) and incident breast cancer were published online in the Journal of Clinical Oncology. The studies, which were conducted by researchers at Skåne University Hospital in Malmö, Sweden and together encompass almost 3,500 subjects, demonstrated a strong association between low plasma concentration of the opioid precursor peptide pro-ENK and increased breast cancer risk in middle-aged and post-menopausal women independent from other possible risk factors.

Although experimental studies have established that enkephalins and related opioid hormones can inhibit the growth of cancer cells, these are the first studies to investigate whether plasma concentration of pro-ENK can predict near-term breast cancer risk in healthy women. The strong association between concentrations of pro-ENK and incident breast cancer found during these studies indicates that pro-ENK is a viable tool for predicting breast cancer risk.

The results represent a potential breakthrough in helping women without a known family history of breast cancer understand their own risk. Current tools such as the GAIL risk score are helpful, but the parameters included in the score are non-modifiable, have only weak prognostic power and do not address an individual’s risk.  And while mammography is effective at detecting early stage breast cancer, there is ongoing concern about over-diagnosis and missed cases. There is a great need for biomarkers that can identify women at highest risk so that appropriate interventional measures can be taken to prevent clinical manifestation of life-threatening breast cancer.

“Our goal is to prevent deaths related to breast cancer,” said Dr. Andreas Bergmann, founder and CEO for sphingotec. “We have now identified two promising biomarkers to achieve this goal:  proneurotensin* (pro-NT) and proenkephalin, which have been demonstrated now in two independent cohorts to predict risk in healthy women. The results of these studies imply great promise for the future of breast cancer prevention. We believe these findings will aid in helping women better understand their breast cancer risk so they can take the appropriate measures for preventing this devastating disease.”

To conduct the first study, Melander et al. measured pro-ENK in fasting plasma from 1,929 healthy women with a mean age of 59 years old participating in the Malmö Diet and Cancer Study (MDCS) and used Cox proportional hazards models to relate pro-ENK to incidence of breast cancer during 15 years of follow up. In the second study, using a case-control design, they sampled 1,569 women from the Malmö Preventive Project with a mean age of 70 years old and used multivariate adjusted logistic regression models to relate pro-ENK and to risk of breast cancer during the observation period.

Results of this study appear online in the Journal of Clinical Oncology.

Authors: Olle Melander, Marju Melander, Jonas Manjer, Peter Almgren, Peter Nilsson, Gunnar Engström, Bo Hedblad, Signe Borquist, Ute Kilger, Jennifer Suhr, Oliver Hartmann, Joachim Struck, Andreas Bergmann and Mattias Belting