IL-9 is a Biomarker of BIA-ALCL Detected Rapidly By Lateral Flow Assay.

ABSTRACT

BACKGROUND: A delayed seroma around breast implants is the most common clinical presentation of BIA-ALCL. However, most seromas are due to benign causes. Therefore, it is essential to distinguish benign seromas from seromas due to BIA-ALCL. In a prior study mean concentrations of IL-9, IL-10 and IL-13 were found to be significantly higher in BIA-ALCL than in benign seromas. OBJECTIVES: The aim of this research was to test the ability to detect high concentrations of IL-9 rapidly with a lateral flow assay (LFA). Because we previously reported that a LFA for CD30 detected BIA-ALCL in seromas we compared CD30 and IL-9 LFAs in distinguishing BIA-ALCL from benign seromas. METHODS: Thirty microliter samples of 26 seromas (15 benign, 11 malignant) were tested on in-house prepared strips for IL-9 and CD30. Nanoparticle-conjugated antibodies specific to IL-9 and CD30 were used for detection. IL-9 was analyzed in undiluted samples and CD30 samples were optimized at 13 dilution. The dynamic range of detection was determined by spiking recombinant IL-9 into a benign seroma. Image analysis measured intensity of both test line (TL) and control line (CL) and a TL/CL ratio was calculated. IL-9 protein and IL-9 transcription factor PU.1 were stained in BIA-ALCL lines and clinical samples. RESULTS: The IL-9 LFA was reliable in distinguishing BIA-ALCL from benign seromas when the concentration of IL-9 was greater than 10 ng/ml. The CD30 LFA was positive in all 11 malignant cases. In one case with only faint CD30 and IL-10 test lines, the IL-9 LFA was clearly positive. Immunohistochemistry showed IL-9 and its essential transcription factor PU.1 were present in tumor cells in BIA-ALCL lines and clinical samples. CONCLUSIONS: IL-9 is a tumor cell biomarker of BIA-ALCL that can be detected by lateral flow assay and immunohistochemistry. Concentrations of IL-9 greater than 10 ng/ml reliably distinguished BIA-ALCL from benign seromas. Moreover, IL-9 LFA could detect BIA-ALCL when CD30 LFA was not definitive and IL-10 was of low concentration with a faint IL-10 TL, suggesting a multiplex LFA including IL-9, CD30 and IL-10 might be more effective in detecting BIA-ALCL in selected cases.