Jonas M. Sheehan

Reflections on Shunt Infection

The placement and revision of ventriculoperitoneal (VP) shunts remains a mainstay in the surgical treatment of hydrocephalus. While the North American infection rate averages nearly 8–10%, published infection rates for VP shunt infection below 1% have been reported. We retrospectively reviewed shunt operations by a single surgeon over 62 months to analyze the infection rate. In 62 months, we performed 526 shunt placements or revisions in patients up to 18 years of age. There were 7 shunt infections (1.33%). In 5 cases, the organism was Staphylococcus epidermidis, and a single shunt each was infected with Haemophilus influenzae and Staphylococcus aureus. Each infection was treated with external ventriculostomy drainage and intravenous antibiotics. The new shunt was placed at a new incision site after at least 5 days of sterile spinal fluid cultures. The mean follow-up among these patients after shunt insertion was 25 months. VP shunting remains the most common operation for hydrocephalus. Infections are linked with seizures, higher future risks of shunt infection and malfunction, and reduced IQ and school performance. Our infection rate during 62 months was limited to 1.33%. Uniform surgical technique, limited hardware and skin edge manipulation and double gloving may be important factors in limiting shunt infections.

HFE polymorphisms influence the response to chemotherapeutic agents via induction of p16INK4A

HFE is a protein that impacts cellular iron uptake. HFE gene variants are identified as risk factors or modifiers for multiple diseases. Using HFE stably transfected human neuroblastoma cells, we found that cells carrying the C282Y HFE variant do not differentiate when exposed to retinoic acid. Therefore, we hypothesized HFE variants would impact response to therapeutic agents. Both the human neuroblastoma and glioma cells that express the C282Y HFE variant are resistant to Temodar, geldanamycin and γ‐radiation. A gene array analysis revealed that p16INK4A (p16) expression was increased in association with C282Y expression. Decreasing p16 protein by siRNA resulted in increased vulnerability to all of the therapeutic agents suggesting that p16 is responsible for the resistance. Decreasing HFE expression by siRNA resulted in a 85% decrease in p16 expression in the neuroblastoma cells but not the astrocytoma cells. These data suggest a potential direct relationship between HFE and p16 that may be cell specific or mediated by different pathways in the different cell types. In conclusion, the C282Y HFE variant impacts the vulnerability of cancer cells to current treatment strategies apparently by increasing expression of p16. Although best known as a tumor suppressor, there are multiple reports that p16 is elevated in some forms of cancer. Given the frequency of the HFE gene variants, as high as 10% of the Caucasian population, these data provide compelling evidence that the C282Y HFE variant should be part of a pharmacogenetic strategy for evaluating treatment efficacy in cancer cells.

Endoscopic extruded screw removal after anterior cervical disc fusion: technical case report.

OBJECTIVE AND IMPORTANCE: Symptomatic complications related to screw migration and extrusion after anterior cervical disc fusion are uncommon. CLINICAL PRESENTATION: We report a case of significant dysphagia owing to late screw migration. INTERVENTION: An endoscopic transpharyngeal removal was performed without pharyngeal closure and with relief of symptoms. CONCLUSION: A transpharyngeal endoscopic approach to remove loose anterior cervical hardware is feasible and warrants further evaluation.

Acute and long-term management of sports-related closed head injuries

Aggressive participation in athletics is rewarded in many ways in our society. As long as there is such strong impetus for participation in athletics, the risks of head injuries for participants will remain. Important strides made in understanding of the pathophysiology of head injuries may lead to improved treatment strategies in the future. In light of the current lack of effective therapies, however, the best options remain injury prevention, early and appropriate recognition, and limitation of subsequent, further injury. Frequently the medical staff is encouraged to allow the athlete to return to play based on the desires of the coach, team, fans, parents, and even the athlete himself. A thorough understanding of the potentially serious risks of repetitive injury, however, mandates that only a proper conservative period of observation and evaluation will best serve the competitor.

COX-2 Drives Metastatic Breast Cells from Brain Lesions into the Cerebrospinal Fluid and Systemic Circulation

Breast cancer is among the most common malignancies that metastasize to the brain, with 15% to 20% of patients with metastatic breast cancer eventually developing brain metastases. We previously reported a method to enumerate tumor cells in the cerebrospinal fluid (CSF) of patients with breast cancer with central nervous system (CNS) metastases, a setting that lacks sufficiently informative biomarkers. Here, we show that breast cancer cells can spontaneously disseminate into the CSF from brain lesions in mice in a COX-2-dependent manner and can escape from the CNS to systemic circulation. Enumeration of tumor cells in the peripheral blood (circulating tumor cells, CTC) and CSF (cerebrospinal fluid tumor cells, CSFTC) of nine breast cancer patients with brain metastases revealed dynamic changes in tumor cell burden in both the peripheral blood and CSF compartments that correlated with clinical disease progression. Interestingly, four of the enrolled patients exhibited rapid intercompartmental transitioning of the disease reflected in the CTC and CSFTC counts that preceded corresponding evidence by clinical imaging or neurologic symptoms. Two of these patients had systemic disease recurrence involving the primary malignant site. Intercompartmental cycling of tumor cells may represent an important mechanism for disease persistence and recurrence that may involve tumor self-seeding. Our findings demonstrate the involvement of COX-2 in the genesis of CSFTCs and suggest that COX-2 inhibitors should be investigated in patients with breast cancer with brain metastases for their ability to reduce CSFTC counts and prevent systemic recurrence.

Detection of circulating tumor cells in the cerebrospinal fluid of a patient with a solitary metastasis from breast cancer: A case report

Brain lesions identified following the diagnosis and eradication of primary cancers are often ambiguous in origin, existing as a solitary metastasis or an independent primary brain tumor. The brain is a relatively common site of metastasis with breast cancer, although determining whether metastases have originated from the breast or brain is often not possible without invasive biopsies. In the current case report, a patient presented with a brain lesion identified by radiography and was without systemic disease. The patient had previously exhibited a complete response to chemotherapy and surgery for a poorly differentiated invasive ductal carcinoma. The origin of the brain lesion could not be determined by magnetic resonance imaging, giving rise to a diagnostic dilemma with diverging treatment options. We previously reported a method to isolate and enumerate tumor cells of epithelial origin in the cerebrospinal fluid (CSF). CSF tumor cell analysis of the patient revealed massive CSF tumor cell burden of epithelial origin, indicating that the brain lesion was likely of breast origin. The current case report highlights the use of CSF tumor cell detection as a differential diagnostic tool, in addition to its previously demonstrated use as a marker of disease burden and therapeutic response.

Abstract 3483: Modeling circulating tumor cells in the peripheral blood and CSF of breast cancer patients.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC The enumeration of circulating tumor cells (CTCs) using the CellSearch system (Veridex LLC) is a valuable prognostic clinical tool in several epithelial malignancies. Surveillance methods for metastatic disease involving the central nervous system (CNS) lack adequate sensitivity, specificity, and reproducibility in the clinic. We previously reported a method to enumerate CTCs in the cerebrospinal fluid (CSF) of breast cancer patients with metastases involving the CNS. The enumeration of CTCs in CSF by this method is highly sensitive, accurate, reproducible, and correlates with disease burden by several measures. Here, we concomitantly monitor CTCs in the peripheral blood and CSF of five patients with neoplastic meningitis receiving intrathecal (IT) chemotherapy. In each patient, CTC counts have been more sensitive than conventional cytology, and have predicted the course of symptoms and overall survival more precisely than conventional cytology. We observed a striking inverse relationship between CTC counts in the peripheral blood and CSF. This observation generated the hypothesis that CTCs migrate from the blood to the CSF and the converse as sanctuary sites during compartmentalized therapy to result in systemic disease recurrence. To test this hypothesis we created mouse models of these clinical phenomena including injection of triple-negative breast cancer into the peripheral blood or intracranially. Injection of luciferase-infected MDA-MB-231 or MDA-MB-468 human triple-negative breast cancer cells into the brain of athymic nude mice resulted in primary tumors at the site of injection. The MDA-MB-231, unlike the MDA-MB-468, generated detectable tumor cell dissemination into the CSF of inoculated mice that correlated with a significantly declined survival. CSF collected from the cisterna magna of inoculated mice corroborated these observations. Current studies are examining the impact of compartmentalized therapy on the migration of these tumor cells as well as profiling unique genetic drivers of the subset of tumors cells that disseminate into the CSF. The intercompartmental cycling of tumor cells may represent an important mechanism for disease persistence and recurrence, and suggests that concurrent systemic and CNS-directed therapy may be warranted. Citation Format: Joshua E. Allen, Akshal S. Patel, David T. Dicker, Jonas M. Sheehan, Michael Glantz, Wafik S. El-Deiry. Modeling circulating tumor cells in the peripheral blood and CSF of breast cancer patients. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3483. doi:10.1158/1538-7445.AM2013-3483

Abstract 5565: Circulating tumor cells in the peripheral blood and cerebrospinal fluid of patients with central nervous system metastases

The enumeration of circulating tumor cells in peripheral blood is a validated method of monitoring disease status in patients with epithelial malignancies involving the breast, colon, prostate, or lung. As cancer therapies improve and aim to decrease metastatic burden, the central nervous system (CNS) is emerging as an important sanctuary site for metastasis. Current surveillance and clinical markers of metastatic disease progression involving the CNS are lacking adequate sensitivity, reproducibility, and specificity. One of these clinical markers is cerebrospinal fluid (CSF) cytology, which lacks clarity, is insensitive, requires high sample volumes and is subject to interpretation bias by the pathologist. To overcome these limitations, we previously adapted the Cellsearch system (Veridex) to isolate and enumerate tumor cells in the CSF of breast or non-small cell lung cancer patients with CNS metastases. We recently reported that the number of cells in the CSF directly correlated with the subject9s clinical condition and Karnofsky performance status (KPS) in metastatic breast cancer. Furthermore, imaging of the neuroaxis in these patients revealed disease presence, however, was not indicative of disease burden. A sharp decline in the number of CSF tumor cells (CSFTCs) was universally noted after the onset and maintenance of such ventricular intrathecal chemotherapy. We have continued to follow these patients and have expanded our patient population to include non-small cell lung cancer. This includes a patient that we have followed from a baseline CSFTC count of >10,000 to zero over the course of intrathecal treatment, which as been accompanied by drastically reduced disease by and complete resolution of clinical symptoms. We have also begun to perform concomitant CTC enumeration from peripheral blood in conjunction with CSFTC analysis. Interestingly, while there appears to be no strong correlation between the two subpopulations, tumor cells seemed to be compartmentalized to either the blood or the CSF. Together, the current data indicates that CSFTCs may serve as viable markers for diagnosis and prognostication in the setting of CNS metastases. This novel method of isolating CSFTCs provides a semi-automated platform that greatly increases sensitivity, accuracy and reliability over the standard CSF cytology. Furthermore, this platform enables studies to elucidate the significance and biology of this unique subpopulation of tumor cells, including its relationship with CTCs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5565. doi:1538-7445.AM2012-5565

Breast Cancer and Renal Cell Cancer Metastases to the Brain

Metastatic tumors from systemic cancers comprise the majority of brain tumors. These tumors most commonly originate from the lung and breast skin or kidney cancers. There are numerous similarities regarding the pathophysiology of these entities. Primary tumors spread to the central nervous system in a stepwise and highly concerted fashion. Tumor particles must breach the containment organ and subsequently travel via the blood stream to lodge within the brain. Trans-endothelial migration allows cells to penetrate the blood brain barrier. Tumor emboli must then survive and grow within the brain microenvironment with local nutrient supply and glial support. Breast and renal tumors utilize an array of similar molecular signals to accomplish these tasks: such as the Ras/MEK/MAPK and PI-3 K/Akt pathways. This may explain why these primaries have a preponderance to metastasize to the brain. As antioncogenic therapies become more effective and patients with systemic cancers are afforded longer survival, cerebral invasion becomes more common and more important to overall management. Based on recent scientific data, emerging therapeutic targets for brain metastasis include vascular endothelial growth factor (VEGF), the epidermal growth factor receptor (EGFR) family, chemokines and mTOR.

Abstract 5410: Down regulating heavy chain ferritin gene increasesthe radiation therapeutic efficacy for treatment of glioma

Gliomas, especially glioblastoma multiforme are resistant to radiation and chemotherapy. Therefore, efforts to develop new course of therapy to enhance efficacy of treatment strategies are obviously critical. We hypothesized that disrupting iron homeostasis in malignant tumor cells could prove effective at negatively affecting tumor growth because cancer cells have a robust iron requirement consistent with their rapid growth and high metabolic rates. The high levels of iron uptake require a mechanism to limit iron induced oxidative damage. This function is the responsibility of ferritin; an iron storage protein with 24 subunits of two types of chains light and heave chains. Heavy chain ferritin (H-ferritin) has been found in the nucleus of tumor cells where it appears to protect DNA from oxidative damage and promote transcription. We hypothesized that silencing the H-ferritin gene could increase the sensitivity of tumors cells to radiation. On the other hand, our previous data already demonstrated that silencing the H-ferritin gene increased chemotherapeutic efficacy for treating gliomas. To test our present hypothesis, the H-ferritin gene will be silenced via a cationic liposome carrying siRNA. We have chosen glioma cell lines (U251, U87 and MNSF) as our in vitro model. Subcutaneous glioma tumor in mouse model (athymic nude mice) was chosen as our in vivo model. Our preliminary in vitro data demonstrated silencing the H-ferritin gene in U251 cells leads to a 50% increase in cell death at 20 Gy for 24, 48 and 72 hours post radiation. Intratumoral injections of cationic liposomes containing H-ferritin siRNA reduced the effective in vivo dose of radiation for tumor suppression by more than 90% at 7 weeks. A supercoil relaxation assay demonstrated that H-ferritin, but not L-ferritin directly protects DNA from radiation by maintaining DNA in a relaxed from. We will further test our hypothesis in glioma-U87, neurofibroma-sNF96.2 and breast cancer-MCF-7 cells. As of now our data shows that silencing the H-ferritin gene appears to be an effective way to increase the sensitivity of the glioma tumors to radiation, which sheds light on increasing the radiation therapeutic efficacy for treatment of malignant tumors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5410. doi:10.1158/1538-7445.AM2011-5410