Detection and Validation of Organic Metabolites in Urine for Clear Cell Renal Cell Carcinoma Diagnosis

Abstract

Background: Clear cell renal cell carcinoma (ccRCC) comprises the majority, approximately 70-80%, of renal cancer cases and often remains asymptomatic until incidentally detected during unrelated abdominal imaging or at advanced stages. Currently, standardized screening tests for renal cancer are lacking, which presents challenges in disease management and improving patient outcomes. This study aimed to identify ccRCC-specific volatile organic compounds (VOCs) in the urine of ccRCC-positive patients and develop a urinary VOC-based diagnostic model.

Methods: This study involved 233 pretreatment ccRCC patients and 43 healthy individuals. VOC analysis utilized stir-bar sorptive extraction coupled with thermal desorption gas chromatography/mass spectrometry (SBSE-TD-GC/MS). A ccRCC diagnostic model was established via logistic regression, trained on 163 ccRCC cases versus 31 controls, and validated with 70 ccRCC cases versus 12 controls, resulting in a ccRCC diagnostic model involving 24 VOC markers.

Results: The findings demonstrated promising diagnostic efficacy, with an Area Under the Curve (AUC) of 0.94, 86% sensitivity, and 92% specificity.

Conclusions: This study highlights the feasibility of using urine as a reliable biospecimen for identifying VOC biomarkers in ccRCC. While further validation in larger cohorts is necessary, this study's capability to differentiate between ccRCC and control groups, despite sample size limitations, holds significant promise.

Keywords: GC-MS; VOCs; ccRCC; diagnostic model; metabolomics; renal cancer carcinoma; stir-bar sorptive extraction; urinary.

Figure 1

The partitioned total patient population used within training and testing cohorts to generate selected VOCs for diagnostic prediction of ccRCC.

Figure 2

Partial least squares discriminant analysis plot (PLS-DA) comparing the urinary VOCs detected in ccRCC and healthy control cohorts.

Figure 3

Heat map of significant VOCs in clear cell renal cell carcinoma (ccRCC) vs. controls samples by Wilcoxon test (p < 0.05). 56 VOCs were predominant in the cancer group urine samples and 227 VOCs were elevated in the controls. The correlation between VOCs and patients ranges from low (red) to high (blue).

Figure 4

(A) The ROC curve for VOC ccRCC diagnosis logistic model verified in the training group with 194 patients (163 ccRCC vs. 31 healthy control). (B) The ROC curve for VOC ccRCC diagnosis logistic model validated in the testing group with 82 patients (70 ccRCC vs. 12 healthy control).

Figure 5

Visual representation of 23 biological pathways generated from the 283 significant VOCs found in the training cohort by Wilcoxon rank-sum test with p < 0.05.