Creatine kinase-BB in the cerebrospinal fluid as a marker of CNS metastases and leptomeningeal carcinomatosis in patients with breast cancer

Inhibition of Jumonji Histone Demethylases Selectively Suppresses HER2+ Breast Leptomeningeal Carcinomatosis Growth via Inhibition of GMCSF Expression

HER2⁺ breast leptomeningeal carcinomatosis (HER2⁺ LC) occurs when tumor cells spread to cerebrospinal fluid-containing leptomeninges surrounding the brain and spinal cord, a complication with a dire prognosis. HER2⁺ LC remains incurable, with few treatment options. Currently, much effort is devoted toward development of therapies that target mutations. However, targeting epigenetic or transcriptional states of HER2⁺ LC tumors might efficiently target HER2⁺ LC growth via inhibition of oncogenic signaling; this approach remains promising but is less explored. To test this possibility, we established primary HER2⁺ LC (Lepto) cell lines from nodular HER2⁺ LC tissues. These lines are phenotypically CD326⁺CD49f^-, confirming that they are derived from HER2⁺ LC tumors, and express surface CD44⁺CD24^-, a cancer stem cell (CSC) phenotype. Like CSCs, Lepto lines showed greater drug resistance and more aggressive behavior compared with other HER2⁺ breast cancer lines in vitro and in vivo. Interestingly, the three Lepto lines overexpressed Jumonji domain-containing histone lysine demethylases KDM4A/4C. Treatment with JIB04, a selective inhibitor of Jumonji demethylases, or genetic loss of function of KDM4A/4C induced apoptosis and cell-cycle arrest and reduced Lepto cell viability, tumorsphere formation, regrowth, and invasion in vitro. JIB04 treatment of patient-derived xenograft mouse models in vivo reduced HER2⁺ LC tumor growth and prolonged animal survival. Mechanistically, KDM4A/4C inhibition downregulated GMCSF expression and prevented GMCSF-dependent Lepto cell proliferation. Collectively, these results establish KDM4A/4C as a viable therapeutic target in HER2⁺ LC and spotlight the benefits of targeting the tumorigenic transcriptional network. SIGNIFICANCE: HER2⁺ LC tumors overexpress KDM4A/4C and are sensitive to the Jumonji demethylase inhibitor JIB04, which reduces the viability of primary HER2⁺ LC cells and increases survival in mouse models.

Novel methods to diagnose leptomeningeal metastases in breast cancer

Leptomeningeal metastases (LM) in breast cancer patients are rare but often accompanied by devastating neurological symptoms and carry a very poor prognosis, even if treated. To date, two diagnostic methods are clinically used to diagnose LM: gadolinium MRI of the brain and/or spinal cord and cytological examination of cerebrospinal fluid (CSF). Both techniques are, however, hampered by limited sensitivities, often leading to a long diagnostic process requiring repeated lumbar punctures and MRI examinations. To improve the detection rate of LM, numerous studies have assessed new techniques. In this review, we present the current workup to diagnose LM, set out an overview of novel techniques to diagnose LM, and give recommendations for future research.

Meningeal carcinomatosis in solid tumors

The involvement of the leptomeninges by metastatic tumors can be observed in solid tumors, in which case it is termed meningeal carcinomatosis (MC), and in lymphoproliferative malignant disease. It is more common in breast and lung cancer, as well as melanoma, with adenocarcinoma being the most frequent histological type. MC is usually a late event, with disseminated and progressive disease already present and, it is characterized by multifocal neurological signs and symptoms. Diagnosis is based on the evaluation of clinical presentation, cerebrospinal fluid and neuroimaging studies. The better systemic disease control is observed with new therapeutic agents, and the development of neuroimaging methods is responsible for the increasing incidence of such metastatic evolution. Intrathecal chemotherapy is generally the treatment of choice, although frequently palliative. Prognosis is guarded, although a higher performance status may indicate a subgroup of patients with a more favorable outcome.

Proteomic analysis of cerebrospinal fluid discriminates malignant and nonmalignant disease of the central nervous system and identifies specific protein markers

CNS diseases are often accompanied by changes in the protein composition of cerebrospinal fluid (CSF). SELDI-TOF-MS provides an approach for identifying specific protein markers of disease in biological fluids. We compared the CSF proteomes from patients with neoplastic and reactive/inflammatory CNS diseases to identify potential biomarkers. SELDI-TOF-MS was performed on CSF derived from lumbar puncture of 32 patients, including 10 with CNS malignancies, 12 with inflammatory or reactive conditions, and 10 with unknown CNS disease. Using the SAX-2 (strong anionic exchange) chip, we uncovered three conserved protein peak ranges within each disease category. For neoplastic diseases, we identified conserved peaks at 7.5-8.0 kDa (9/10 samples), 15.1-15.9 kDa (8/10 samples), and 30.0-32.0 kDa (5/10 samples). In reactive/inflammatory diseases, conserved peaks were found at 6.7-7.1 kDa (10/12 samples), 11.5-11.9 kDa (12/12 samples), and 13.3-13.7 kDa (9/12 samples). A protein from the 30.0 to 32.0 kDa peak range found in neoplastic CSF was identified by MALDI analysis as carbonic anhydrase, a protein overexpressed in many malignancies including high-grade gliomas. Similarly, cystatin C was identified in the 13.3-13.7 kDa peak range in non-neoplastic CSF and was most prominent in inflammatory conditions. Our approach provides a rational basis for identifying biomarkers that could be used for detection, diagnosis, and monitoring of CNS diseases.

Cerebrospinal fluid analysis in clinical diagnosis

Images

Carcinomatous meningitis in solid tumours

Carcinomatous meningitis (CM) is an uncommon but devastating complication of malignancy. The management is controversial and clear recommendations cannot be made because: 1) Most series include patients with CM that has arisen from different primary malignancies which are associated with different median survival intervals. 2) There have been no prospective randomised investigations of treatment modalities in patients with CM from a particular tumour type. 3) The definition of response varies from one report to another so that some response rates refer to cytological changes in the CSF while others take clinical, cytological and biochemical parameters into account. 4) Reports include patients with and without parenchymal metastases and the natural history of carcinomatous meningitis in the two situations may differ. The median survival of solid tumour carcinomatous meningitis (excluding leukaemia and lymphoma) is approximately 2-3 months and patients with breast cancer have the longest survival (median 3 months). Currently patients are treated with radiotherapy to part or all of the neuraxis with either intrathecal or intravenous chemotherapy but the relative contribution of these modalities to survival or quality of life remains unknown. Approximately 50% of patients with carcinomatous meningitis die from other causes, including systemic disease. The two most important endpoints for the patient, neurological improvement and overall survival, are seldom used in isolation in the literature. Many reports have focused on surrogate markers of response, namely biochemical and cytological data points but the correlation between clinical status and these parameters is poor because of differences between lumbar and ventricular CSF and disturbances of CSF flow in CM. The current literature does not provide clear guidelines for the treatment of this condition. Multicentre, prospective, randomised trials should be conducted that address questions of most relevance to the patient, namely neurological status and overall survival.

Creatine kinase BB isoenzyme levels in tumour cytosols and survival of breast cancer patients

Creatinine kinase BB (CK-BB) is elevated in many tumours including those of the breast. We have recently described a new, highly sensitive and specific method for measuring CK-BB, based on monoclonal antibodies and time-resolved fluorometry. Using this method, we quantitated CK-BB in 172 breast tumour cytosols and examined the associations between CK-BB and other clinicopathological variables and patient survival. High CK-BB levels were seen more frequently in tumours from patients who were younger (age < 50 years), patients who qualified for chemotherapy and patients with oestrogen receptor-positive tumours. No association was seen between CK-BB and tumour stage, grade, size, histological type or the progesterone receptor. In univariate analysis, the risk of relapse or death was higher in the group with tumours containing high CK-BB levels but the difference did not reach statistical significance. In multivariate analysis, the risk of death was statistically significantly higher in the high-CK-BB group. Analysis of subsets of patients revealed that patients with oestrogen receptor-negative cancer have higher risk of death if their tumours contain high levels of CK-BB. Our data suggest that, in general, CK-BB is associated with more aggressive tumours but its value as a prognostic indicator is limited. CK-BB content of breast tumours may be more useful as an aid in selecting therapy directed at inhibiting this enzyme activity and thus depriving tumour cells of their energy source.

Enzymatic changes in the cerebrospinal fluid in patients with infections of the central nervous system

Enzymatic determinations in cerebrospinal fluid (CSF) of aspartate aminotransferase (AST), lactic dehydrogenase (LDH), gammaglutamyl transpeptidase (GGT), creatine phosphokinase (CPK) and creatine kinase BB (CK-BB) were performed in 16 patients with aseptic meningitis (AM), in 25 children with bacterial meningitis (BM) and in 15 patients with meningism. The activity of AST and GGT was significantly higher in patients with BM on admission compared with those with AM and meningism (p < 0.05 and p < 0.005, respectively) and decreased with therapy. The highest concentration of AST and LDH appeared in patients with poor outcome as well as in those with ventriculomegaly on neurosonography (p < 0.05). The concentration of CK-BB increased in all patient groups on admission and remained higher on termination of therapy. The present study confirms the high activity of AST and GGT in BM patients in the CSF whereas the increased activity of AST and LDH reflects the extent of brain injury. Nevertheless, the prognosis for individual patients cannot be established on the basis of enzyme activity alone, but depends on several factors.

Diagnostic value of cerebrospinal fluid cytology in comparison with tumor marker activity in central nervous system metastases secondary to breast cancer

BACKGROUND

Central nervous system (CNS) metastases occur in approximately 35% of patients with breast cancer. Parenchymal brain metastases (MET) remain undetected in a large proportion of patients, and only 50% of patients with leptomeningeal carcinomatosis (MC) are diagnosed in vivo.

METHODS

Cytology and activity of the tumor markers tissue polypeptide antigen (TPA) and creatine kinase-BB isoenzyme (CK-BB) were evaluated in the cerebrospinal fluid (CSF) in 71 consecutive patients with breast cancer suspected for CNS metastases.

RESULTS

Forty-three patients had no CNS metastases, 12 patients had MET, 5 patients had both MET and MC, and 11 patients had MC alone. Seven of the patients with MC had an intracerebroventricular (ICV) reservoir inserted, and an additional 70 ICV CSF samples from these patients were obtained. In CSF obtained by lumbar puncture, 11% of the samples were classified as "suspicious for malignancy," but a very limited interobserver variability was demonstrated (Kappa test value, 0.81; 95% confidence limits, 0.67-0.95%). Fifty-one percent of the ICV CSF samples were classified as "suspicious for malignancy" (Kappa test value, 0.58; 95% confidence limits, 0.34-0.82%). TPA and CK-BB were both measured in 101 CSF specimens (61 from lumbar puncture and 40 ICV samples). The differences between patients with and without CNS metastases were significantly different according to TPA (P < 0.00001) and CK-BB (P < 0.00003; Mann-Whitney test). The sensitivity and predictive value of a negative test for having any CNS metastases (in case of elevated values of either TPA or CK-BB or both) were 85% (95% confidence limits, 65-96%) and 90% (95% confidence limits, 76-97%), respectively. In addition, a significant correlation between TPA and CK-BB was demonstrated in CSF from lumbar puncture (Spearmans-Rho, 0.49; P < 0.0001) and ICV (Spearmans-Rho, 0.37; P < 0.02).

CONCLUSIONS

Cytologic evaluation of CSF obtained by lumbar punctures is a reliable procedure. In CSF from ICV reservoirs, cytologic evaluation is of limited use, but CK-BB and TPA is of potential value.