Objectives: We have shown previously a panel of 7 salivary mRNA biomarkers for oral cancer detection. We aimed to validate these salivary markers in a phase 2 biomarker study which was conducted in a blinded manner simultaneously by the Biomarker Reference Laboratory (BRL) of the NCI's Early Detection Research Network (EDRN) and our laboratory.
Methods: Anonymised aliquots of saliva samples (n=64) were distributed to two different individuals from each laboratory. Total RNA was isolated semi-automatically (KINGFISHER, Thermo Scientific) and the expression of these biomarkers were quantified by a novel multiplex RT-PCR preamplification and subsequent singleplex real-time PCR. All reactions were loaded automatically (BioMek 3000) in 96-well plates. Data (Ct numbers and relative copy numbers) were then reported to and analyzed by statisticians at EDRN Data Management and Coordinating Center.
Results: 1. Highly comparable results were generated in both labs (Table). 2. Three genes for EDRN-BRL and all 7 from our lab, were elevated in oral cancer samples significantly (p<0.05). 3. Area under the curve (AUC) of 0.86 and 0.85 were achieved by EDRN-BRL and our lab, respectively (7 marker combined).
Conclusion: The predictive power and standardized measurement of these salivary oral cancer biomarkers were highly reproducible. Importantly, they were independently validated by NCI's EDRN. A second validation (n=100) is currently underway prior to a phase 3 multi-center validation.
Genes | Area under ROC curve | Wilcoxon P-value | False Discovery Rate | |||
| EDRN | Wong | EDRN | Wong | EDRN | Wong |
IL8 | 0.775 | 0.798 | <0.001 | <0.001 | 0.091 | <0.001 |
IL1B | 0.677 | 0.717 | 0.024 | 0.005 | 0.056 | 0.006 |
H3F3A | 0.635 | 0.676 | 0.088 | 0.023 | 0.002 | 0.017 |
OAZ1 | 0.652 | 0.676 | 0.053 | 0.023 | 0.084 | 0.017 |
S100P | 0.628 | 0.685 | 0.055 | 0.017 | 0.068 | 0.018 |
SAT | 0.709 | 0.721 | 0.007 | 0.004 | 0.026 | 0.008 |
DUSP1 | 0.594 | 0.665 | 0.144 | 0.034 | 0.129 | 0.021 |
Supported by PHS NIH Grant R01 DE15970 (D.T.W.) and NIH/National Cancer Institute 5U24 CA08636607 (D.C.).