Abstract 2283
Background
Molecular testing is becoming an important part of the diagnosis of any patient with cancer. The challenge to laboratories is to meet this need, using reliable methods and processes to ensure that patients receive a timely and accurate report on which their treatment will be based. The aim of this abstract is to analyzed the benefit of the introduction in the clinical practice of a multigenic platform on the management of metastatic colorectal cancer (CRC).
Methods
DNA extraction by BiOstic Tissue DNA Isolation kit from tumor after microdissection (>20% tumoral cells). k-ras exon 2 mutations by Sanger sequencing in 277 CRC, by pyrosequencing (KRAS status, Diatech Pharmacogenetics) in 538 CRC; n-ras and b-raf mutations by pyrosequencing (NRAS and BRAF status, Diatech Pharmacogenetics) only in k-ras wt CRC from 01/2014. K-ras, n-ras, b-raf and pik3ca mutations by Maldi-TOF Mass Spectrometry (MassArray Agena Bioscence) with Myriapod Colon Status (Diatech Pharmacogenetics) in 170 CRC.
Results
The mutations frequencies were 41.5% k-ras by Sanger sequencing; 46.1% k-ras, 4.0% n-ras and 5.3% b-raf by pyrosequencing; 47.6% k-ras, 8.2% n-ras, 7.1% b-raf, 12.3% pik3ca by MassArray. For all genes the change of methodology has improved the diagnostic sensitivity of test. The introduction of multigenic platform allowed the simultaneous analysis of k-ras, n-ras, b-raf and pik3ca mutations in all patients with CRC, avoiding the step by step analysis approach constrained by a single gene methodology. The comparison of technical features is listed in the table.
| Sanger Sequencing** | Pyrosequencing | MassArray | |
|---|---|---|---|
| Amount of DNA | 200 ng | 350 ng | 160 ng |
| Contamination | Likely | Possible | Rare |
| Analytical Sensitivity | 10-20% | 5-7.5% | 2.5-5% (b-raf 10%) |
| Specificity | 100% | 100% | 100% |
| Consumable cost/patient* | 50 euro | 400 euro | 200 euro |
| Hands-on time | 4 h | 4h | 2.5 h |
| Overall time to results from the DNA | 2.5 days | 2.5 days | 1 day |
| Difficulties of data interpretation | Intermediate | Intermediate | Low |
| CE/IVD Validation | No | Yes | Yes |
* Cost determined on the basis of 5 patients/run. **Only k-ras exon 2
Conclusions
The introduction in the routine diagnostics of a multigenic platform is clearly an attractive approach to increase the quality and the rapidity of molecular analysis results, that can be translate in a better clinical management of metastatic colorectal patient.
Clinical trial identification
Legal entity responsible for the study
Humanitas Research Hospital
Funding
National Health System
Disclosure
All authors have declared no conflicts of interest.