CTC count with gene expression profiling is a novel breast cancer biomarker with potential for personalized treatment. Its feasibility & clinical utility in low-resource centers has not been evaluated. Facilitating this technology poses numerous challenges: cost, availability, undefined risk-benefit ratio & outcome among Filipinos & not yet a standard approach. Primary objective is to describe CTC count & gene expression profile of Filipino breast cancer patients. This is the first Filipino data on CTCs.
Charts of breast cancer patients who underwent the procedure at participating hospitals from January 2014 to August 2015 were reviewed. CTC count was done on blood extracts using EpCam-targeted magnetic beads, followed by immunofluorescence validation of cell surface markers (i.e., DAPI+ CD45- CK+). Gene expression profiling was done through Real Time PCR of buffy coat RNA extracts using three tumor associated-genes (i.e., CD133, CK19 & MUC1). Tumor subtypes were determined by IHC. FISH was done in Her2 equivocal findings.
74 patients underwent CTC evaluation, of which, 47 were eligible for study. Median age was 57 +/- 9. Stages I, II, III, IV account for 11%, 38%, 34% & 17% respectively. Luminal A, Luminal B Her2 negative, Luminal B, Her2 enriched, TNBC represent 51%, 2%, 23%, 13% & 11% respectively. CTC count ranged from 0-29 (mean: 2). CTC counts were determined: post standard of care (89%), during surveillance (9%) & at baseline (2%). CTC count after 6 months in 23%, showed values from 0-3 (mean: 1.1).
CD133, CK19 & MUC1 Expression Among BRCA Subtypes N 19
|Luminal A N 7||4||57||MUC1|
|2||29||CD133 & MUC1|
|Luminal B Her2 neg N 1||1||100||MUC1|
|Luminal B N 4||3||75||MUC1|
|Her2 enriched N 4||2||50||MUC1|
|TNBC N 3||2||67||MUC1|
|1||33||CD133 & MUC1|
Median turn-around time from request to result was 7 days (range 5-10).
CTC with gene expression profiling is feasible in low-resource center. Its clinical usefulness reflects aggressive monitoring & treatment strategies in elevated CTC count (>3), upregulated CD133, CK19 & MUC1. Further research is needed to overcome challenges, increase utility, gain gene expression knowledge among Filipinos, provide better leads for treatment & improve survival.
Clinical trial identification
All authors have declared no conflicts of interest.