Abstract
1104 Background: Leptomeningeal diseases (LMD) from breast cancer are detected in up to 19% of patients with brain metastasis and their prognosis is extremely poor. Diagnosis of leptomeningeal disease requires positive cerebrospinal fluid (CSF) cytology. However, it is not known whether HER2 status of malignant CSF cells coincides with that of original breast carcinoma cells. We intended to determine whether CSF cytology specimen is suitable for evaluating HER2 status by fluorescence in situ hybridization (FISH) in LMD to provide the basis for HER2 targeted intrathecal therapy. Methods: Both formalin-fixed paraffin-embedded (FFPE) breast carcinoma tissue and liquid based CSF cytology specimen were tested for HER2 status in 16 patients who developed LMD at National Cancer Center between Dec 2004 and Jul 2008. We evaluated HER2 gene amplification by FISH on destained CSF cytology slides which contained minimum 20 malignant cells per slide, and compared with HER2 status by immunohistochemistry (IHC) in FFPE breast carcinoma tissue. HER2 was determined positive when FISH ratio > 2.2 or IHC 3+ according to ASCO/CAP guideline. Results: Concordance rate of HER2 status between CSF cytology by FISH and FFPE tissue by IHC was 100% as shown in the table. Conclusions: When CSF cytology specimen was appropriately prepared yielding adequate cellularity without dry artifact, CSF cytology was suitable for evaluating HER2 status by FISH in LMD. Intrathecal HER2 targeted therapy could be attempted when FFPE breast carcinoma tissue is HER2 positive in view of highly concordant HER2 status by our data. Supported by NCC Grant No 0610240- 3. [Table: see text] No significant financial relationships to disclose.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call