Clinical significance of detecting CSF-derived tumor cells in breast cancer patients with leptomeningeal metastasis

Abstract

Despite marked advances in breast cancer therapy, breast cancer-associated leptomeningeal metastasis (LM), a particularly aggressive syndrome with multifocal seeding of the leptomeninges by tumor cells, still carries an abysmal prognosis. A major problem with breast cancer LM surveillance is the lack of an effective and sensitive means to track dynamic changes of the disease. Cytology detection of cerebrospinal fluid (CSF) is considered the gold standard for LM diagnosis but has a high false-negative rate with a limited sensitivity. Here we applied subtraction enrichment and immunostaining-fluorescence in situ (SE-i•FISH) method, a technique previously used for isolating circulating tumor cells (CTCs) from the peripheral blood, to detect, enumerate, and track cerebrospinal fluid-derived tumor cells (CSFTCs) in CSF samples from 8 breast cancer patients. Comparing with cytology test, we found SE-i•FISH method can accurately and feasibly detect CSFTCs for the diagnosis of breast cancer-associated LM and monitor the disease progression. We also isolated and cultured CSFTCs from these cancer patients and performed genomic sequencing on CSFTCs of two patients. Genomic analysis of CSFTCs against corresponding archival primary breast tumors revealed clonal relationships with some ongoing evolution. Further drug sensitivity test on cultured CSFTCs based on genomic analysis data helped identify promising treatment options for the patient tested. Together, our results suggest that CSFTCs detection using SE-i•FISH platform could serve as a sensitive and accurate method to make the diagnosis and a promising approach to monitor tumor dynamics and treatment response for breast cancer-associated LM.

Liquid biopsy in central nervous system metastases: a RANO review and proposals for clinical applications

“…Two groups performed genomic sequencing of isolated breast cancer cells in the CSF of LM patients showing mutations identical to the primary breast cancer as well as new mutations suggesting clonal diversity. 33,34 A recent study 8 performed on cells isolated from CSF of non–small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations or anaplastic lymphoma kinase rearrangements and LM has shown that the genetic profiles of CTCs were highly concordant with the molecular alterations present in the primary tumor (89.5%), and some clinically relevant resistance mutations (EGFR T790M, methionine amplifications, Erb-B2 receptor tyrosine kinase 2 [ERBB2] amplifications) were uncovered.…”

GM-CSF signaling is critical for HER2+ breast leptomeningeal carcinomatosis

“…Methotrexate (MTX), a DNA alkylating drug, is frequently used as palliative ITC for HER2+ LC9, 30, 31, 32, 33. However, this approach has very limited success and causes serious side effects26, 27,28,29. Furthermore, patients with HER2+ LC are excluded from clinical trials because of their poor prognosis and to minimize results that are not reproducible1, 34,35,36. Thus, our capacity to identify effective drugs to treat HER2+ LC is limited.…”

Aneuploid CTC and CEC

“…Rapidly enriched viable tumor cells, unperturbed by antibody resistance and free of hypotonic damage, are eligible for primary tumor cell culture and a series of downstream analyses. Recently, epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) target therapy (Gefitinib/Irresa ® ) oriented examination of EGFR mutations, performed on the enriched single non-small cell lung cancer CTCs [ 63 ], and NGS-guided in vitro drug screening carried out on the cultured metastatic breast cancer cells enriched from patient’s cerebrospinal fluid by SE, to successfully select the chemotherapeutic agent palbociclib (the synthetic CDK4/6 inhibitor) upon the identification of a single nucleotide variant (SNV), have been reported [ 64 ].…”

“…Since i•FISH ® technology was reported for the first time on gastric CTC study [ 23 ], stepwise substantial improvement has been systematically built up to yield maximum efficiency and optimized flexibility for expeditious in situ co-detection of multiple tumor biomarkers or relevant proteins (such as PD-L1, CK, EpCAM, Vimentin, human epidermal growth factor receptor 2 (HER2), CD44, CD133, PSMA, GFAP, CD31, etc. ), and aneuploidy of chromosome in CTCs at once [ 8 , 28 , 40 , 64 ]. “iFISHed” CTCs are classified into diverse subtypes by their identified tumor biomarker(s) and chromosome ploidy.…”