Molecular biologists from the Ruđer Bošković Institute (RBI), Sven Ljubić, Antonio Sermek, Isidoro Feliciello,  Đurđica Ugarković, in collaboration with the group of Prof Ana Fröbe, Head of the Department of Oncology and Nuclear Medicine at the Clinical Hospital Center (KBC) of the Sisters of Mercy, discovered a new blood marker for metastatic prostate cancer.

The research was conducted as part of the project funded by Adris Foundation, entitled 'Alpha-satellite RNA: a candidate for diagnostic / prognostic blood biomarkers of prostate cancer' led by Dr Đurđica Ugarković, and the results were published in the scientific journal Genes.

Prostate cancer is the second most common cancer in men in Croatia, and Croatia is among the ten European Union (EU) countries with the highest mortality rate from this disease. New data show that the prostate cancer survival rate in Croatia is lower than the European average, i.e. the five-year survival rate in Croatia is 71.2 percent, while the European average is 83.4 percent.

It is believed that the combination of detecting the disease as early as possible and adopting the latest treatment trends can bring the prostate cancer survival rate in Croatia closer to the European average.

Sven Ljubić, doktorand u Laboratoriju za evolucijsku genetiku IRB-a

The most clinically recognized marker for the diagnosis of prostate cancer is PSA (prostate specific antigen), a serine protease in the kallikrein family, which is produced by the epithelial cells of the prostate and whose levels are usually elevated in prostate cancer patients.

The introduction of PSA testing in asymptomatic men has led to earlier detection of the disease. PSA also allows early detection of latent prostate cancer, which often does not develop into disease and is elevated in benign conditions such as inflammation, and this lack of specificity leads to overdiagnosis.

PSA is also used to monitor disease development, although its level in patients with metastatic prostate cancer does not correlate with the stage of disease development. Due to the lack of specificity of PSA as a diagnostic and prognostic marker, scientists around the world are making additional efforts to find alternative markers for prostate cancer.

Satellite DNA belongs to the group of non-coding DNAs, and alpha-satellite DNA is the most abundant human satellite DNA, accounting for approximately 5 percent of the genome and transcribed into alpha-satellite RNA.

A study by the Sisters of Mercy RBI and KBC Group has shown that metastatic castration-resistant prostate cancer can be reliably distinguished from metastatic hormone-sensitive prostate cancer based on the level of non-coding alpha-satellite RNA in patients' blood. The level is nearly identical in these two types of metastatic disease.

"Based on the level of alpha-satellite RNA, it is possible to reliably distinguish metastatic castration-resistant prostate cancer from localized primary tumours and healthy controls," explains Sven Ljubić, first author and PhD student in the Laboratory for Evolutionary Genetics at RBI.

"These results open the possibility of using the level of alpha-satellite RNA as a simple blood test or as a marker for the diagnosis of metastatic castration-resistant prostate cancer and for monitoring the evolution of metastatic disease," concludes Dr Đurđica Ugarković, the corresponding author and head of the Laboratory for Evolutionary Genetics of RBI.