Identification of Sarcosine as a Target Molecule for the Canine Olfactory Detection of Prostate Carcinoma

Abstract

The hypothesis that dogs can detect malignant tumours through the identification of specific molecules is nearly 30 years old. To date, several reports have described the successful detection of distinct types of cancer. However, is still a lack of data regarding the specific molecules that can be recognized by a dog’s olfactory apparatus. Hence, we performed a study with artificially prepared, well-characterized urinary specimens that were enriched with sarcosine, a widely reported urinary biomarker for prostate cancer (PCa). For the purposes of the study, a German shepherd dog was utilized for analyses of 60 positive and 120 negative samples. Our study provides the first evidence that a sniffer dog specially trained for the olfactory detection of PCa can recognize sarcosine in artificial urine with a performance [sensitivity of 90%, specificity of 95%, and precision of 90% for the highest amount of sarcosine (10 µmol/L)] that is comparable to the identification of PCa-diagnosed subjects (sensitivity of 93.5% and specificity of 91.6%). This study casts light on the unrevealed phenomenon of PCa olfactory detection and opens the door for further studies with canine olfactory detection and cancer diagnostics.

Towards sarcosine determination in urine for prostatic carcinoma detection

“…Although the measurements in blood have been reported as unremarkable, significantly elevated levels in urine have been recorded in some studies, for patients with prostate cancer. Furthermore, in a recent study cancer sniffer dogs were able to distinguish artificial urine samples that had been doped with sarcosine, with 90% success rate [17]. The possible role of sarcosine is however still strongly debated [18], but some recent studies have suggested that sarcosine exhibits considerable stimulatory effects on growth in malignant/metastatic prostate cells [19], possibly due to accumulation in the tumor and consequential conversion to serine and glycine, thereby providing tumor growth promoters [20,21].…”

PI3K-regulated Glycine N-methyltransferase is required for the development of prostate cancer

“…However, these results remain controversial, according to various follow-up studies in different PCa cohorts [ 50 ]. Moreover, many groups have attempted the development of methods to monitor sarcosine abundance [ 51 – 53 ], and combination of sarcosine with other metabolites has been tested in order to test its prognostic potential [ 54 ]. The opposed regulation of GNMT expression by AR vs .…”

Targeted Metabolomics Identifies Plasma Biomarkers in Mice with Metabolically Heterogeneous Melanoma Xenografts

“…We propose seven plasma metabolites as potential melanoma biomarkers, including beta-alanine, p -cresol sulfate, sarcosine, tiglylcarnitine, Hex2Cer (d18:1/16:0), Hex2Cer (d18:1/20:0), and PC ae C42:4, to distinguish healthy from melanoma-bearing mice. Of those seven metabolites, sarcosine is a well-established urine biomarker for prostate cancer [ 54 , 55 , 56 ]. However, to our knowledge, sarcosine has not yet been reported as biomarker for melanoma.…”