Leukocyte Telomere Length (LTL): a biomarker for prostate cancer
Leukocyte telomere length (LTL) is one of the main variables being measured in the ONCOCHECK project from blood samples of every subject participating in one of the six clinical studies that Life Length is carrying out including prostate cancer. This study will involve 1,200 men presenting PSA (prostate-specific antigen) levels above 3 ng/mL and/or a positive rectal examination.
Prostate cancer is the most common cancer among men. Earlier this year, Drs. Ulrika Svenson, Göran Roos, Pernilla Wikström from Umeå University in Sweden published the article “Long leukocyte telomere length in prostate cancer patients at diagnosis is associated with poor metastasis-free and cancer-specific survival” in the journal Tumor Biology. In this study, the authors decided to evaluate the potential of LTL as a biomarker for prostate cancer. To do so, they collected blood samples from 272 individuals including 110 patients with newly diagnosed, localized prostate cancer and 162 control subjects and measured LTL using qPCR. The results obtained revealed that LTL is an independent prognosis factor at diagnosis. Prostate cancer-specific and metastatic free survival was significantly poorer for patients with long LTL, compared to patients with short LTL.
The conclusions from the previous mentioned study indicate that LTL may, therefore, be used as a prognostic marker in malignancy. These results support previous findings where patients with longer LTL have a worse outcome in breast, kidney, colorectal and hepatocellular carcinoma (references: 1, 2, 3, 4). Together, these results suggest that telomere-associated variables (TAVs) testing could be one of the “liquid” cancer tests to be used in the future for greater accuracy minimizing biopsies. Indeed, biopsies are highly relevant in prostate cancer and are currently the most reliable diagnostic procedure yet the number of false negative is still sub-optimal for a definitive determination. In the United States alone, there are over 1,300,000 prostate biopsies annually but only around 230,000 new cases of prostate cancers are actually diagnosed, demonstrating an enormous imbalance in the efficacy of the procedure. Not only do these hundreds of thousands of unnecessary biopsies cost more than $1 billion per year; prostate biopsies are invasive and may lead to infections, urinary incontinence or erectile dysfunction and have been shown that they are not error-free.. Therefore, minimally invasive tests, such as blood tests, are needed to improve early state prostate cancer diagnosis. We are very excited about the study LL-HURS-ONC001 of the Oncocheck project in which a thorough evaluation of the role fo TAVs could result in scoring values with improved sensitivity and specificity to help in diagnosis and prognosis for prostate cancer.