PIK3CA mutations in serum DNA are predictive of recurrence in primary breast cancer patients

Abstract

We attempted to develop a highly sensitive and specific method for the detection of circulating tumor DNA (ctDNA) using a digital PCR (dPCR) assay for PIK3CA mutations (i.e., H1047R, E545K, and E542K) in primary breast cancer patients. The sensitivity of the dPCR assay for the mutant alleles was examined using cell lines with PIK3CA mutations and proved to be 0.01 %. Serum samples were collected pre-operatively from 313 stage I-III breast cancer patients, of whom 110 were found to have PIK3CA mutant tumors. The serum samples from these patients with PIK3CA mutant tumors were subjected to the dPCR assay, and 25 (22.7 %) were found to be positive. No PIK3CA mutant ctDNA was detected in the serum samples of 50 healthy women and 30 breast cancer patients with PIK3CA non-mutant tumors. The patients with PIK3CA mutant ctDNA were dichotomized into mutant ctDNA-high (ctDNA(high)) and ctDNA-low (ctDNA(low)) groups based on the median. The ctDNA(high) patients exhibited significantly shorter recurrence-free survival (RFS; P = 0.0002) and overall survival rates (OS; P = 0.0048) compared to those exhibited by the combined ctDNA(low) patient and ctDNA-free patient group. Multivariate analysis revealed that ctDNA(high) status significantly predicted poor RFS and OS and did so independently of conventional histological parameters. These results suggest that dPCR is a highly sensitive and specific method for the detection of PIK3CA mutant ctDNA and that ctDNA(high) but not ctDNA(low) status is a significant and independent prognostic factor for primary breast cancer patients.

WITHDRAWN: Prognostic value of circulating tumor DNA in breast cancers

“…Recently, multiple studies have investigated the correlation between the presence of ctDNA and prognosis among breast cancer patients. An overwhelming majority of the evidence has shown a correlation between poor prognosis and the presence of ctDNA in breast cancer [17][18][19][20], but several studies have failed to draw similar conclusions [21][22]. Therefore, the prognostic value of ctDNA in breast cancer patients remains controversial.…”

Detection of the <i>PIK3CA</i> Mutation in Circulating Tumor DNA as a Possible Predictive Indicator for Poor Prognosis of Early-Stage Breast Cancer

“…In our study, by contrast, we directly quantified the ctDNA without pre-amplification by ddPCR and adopted the cut-off value of 0.1%, ten-fold higher than that in the study by Beaver et al [10], considering the difference in the detection rate of mutation in the platform by RainDance Technologies (Billerica, MA, USA) in their analysis and in that by Bio-Rad Laboratories (Hercules, CA, USA) in our analysis. It is also interesting that the detection rate of pre-surgery ctDNA in early breast cancer was reported to be 23% in another retrospective study using serum as a source of ctDNA [11], suggesting that serum would be less appropriate for this type of analysis.…”

Liquid biopsy, an innovation of modern medicine

“…PIK3CA mutation detected by digital PCR assay in breast cancer patients is an independent and significant prognostic factor. [13] Detection of new therapeutic targets or reversion of old targets and primary and secondary resistance Detection of resistance mechanisms is the heart of the precision medicine. Analysis of T790M by next generation sequencing of ctDNA in EGFR amplified NSCLC patient's resistance to 1 st line TKI helps us to decide for further treatment in such The importance of repeated Her2/Neu assessment in metastatic breast cancer cannot be over emphasized especially to detect conversion from negative to positive Her2 status.…”