Liquid biopsy – Urine as a sample type
Early detection of cancer can greatly increase chances of survival and improve overall quality of life. Traditionally, a tissue biopsy is the common approach to diagnose many cancers. However, obtaining a tissue sample is not always feasible and the process can be invasive, painful, expensive, time intensive, difficult to perform and requires the intervention of a clinician (1). Further, due to intratumor heterogeneity, a tissue biopsy may not always reflect the entire tumor landscape.
To successfully cure patients with prostate cancer it is important to detect the disease at an early stage. Current screening techniques are based on a measurement of serum prostate specific antigen (PSA) levels and a digital rectal examination (DRE). Drawbacks of PSA testing are its low sensitivity and specificity. Because of the ease of collection and the fact that prostate cells are directly released into the urethra through prostatic ducts after DRE or prostate massage, urine has become the future of non-invasive biomarker testing.
Strains of HPV, in particular HPV16 and 18 have been linked to cause most cervical cancer cases. This cancer type usually does not present any symptoms until it reaches an advanced stage, making early detection and treatment challenging. While women are invited to have a cervical sample through public screening programs, participation remains low in many areas. Urine can help increase participation and reach women that traditionally do not participate in cervical cancer screening programs.
Early detection of bladder cancer can improve chances of survival. However, current detection methods are costly, invasive and can be uncomfortable for the patient. Given the function of the bladder, urine as a sample type is promising. Biomarkers, in particular, micro RNAs (miRNAs) are being investigated.