M. Fatih Okcu

Glutathione S-transferase polymorphisms and survival in primary malignant glioma

Purpose: The purpose of this research was to investigate the relationship between glutathione S-transferase (GST) polymorphisms and survival, and chemotherapy-related toxicity in 278 glioma patients. Experimental Design: We determined genetic variants for GSTM1, GSTT1, and GSTP1 enzymes by PCR and restriction fragment length polymorphisms. We conducted Kaplan-Meier and Cox-proportional hazard analyses to examine whether the GST polymorphisms are related to overall survival, and logistic regression analysis to explore whether the GST polymorphisms are associated with toxicity. Results: For patients with anaplastic astrocytoma, anaplastic oligodendroglioma, anaplastic oligoastrocytoma, and anaplastic ependymoma (n = 78), patients with GSTP1*A/*A-M1 null genotype survived longer than did the rest of the group (median survival “not achieved,” and 41 months, respectively; P = 0.06). Among patients treated with nitrosoureas (n = 108), those with GSTP1*A/*A and GSTM1 null genotype were 5.7 times (95% confidence interval, 0.9–37.4) more likely to experience an adverse event secondary to chemotherapy, compared with the others. Conclusions: In patients with anaplastic astrocytoma, anaplastic oligodendroglioma, and anaplastic oligoastrocytoma, combination of germ-line GSTP1*A/*A and GSTM1 null genotype confers a survival advantage. Patients with this genotype also have an increased risk of adverse events secondary to chemotherapy that primarily comprised nitrosourea alkylating agents.

Screening for Neurocognitive Impairment in Pediatric Cancer Long-Term Survivors

PURPOSE Recent studies suggest that up to 40% of childhood cancer survivors may experience neurocognitive problems, a finding that has led the Childrens Oncology Group to recommend regular evaluation. However, for a variety of reasons, including costs, time restraints, health insurance, and access to professional resources, these guidelines are often difficult to implement. We report reliability and validity data on a brief neurocognitive screening method that could be used to routinely screen patients in need of comprehensive follow-up. PATIENTS AND METHODS Two hundred forty consecutive patients were screened during their annual visits to a long-term survivor clinic using standard neurocognitive measures and brief parent rating. From this total, 48 patients had a second screening, and 52 patients had a comprehensive follow-up evaluation. Test-retest reliability and predictive and discriminative validity were examined. RESULTS Good test-retest reliability was demonstrated, with an overall r = 0.72 and all individual subtest correlations greater than r = 0.40. Although means tended to improve from first to second testing, no significant changes were detected (all P > .10). The screen accurately predicted global intellect (F(6,45) = 11.81, P < .0001), reading skills (F(6,45) = 4.74, P < .001), and mathematics (F(6,45) = 3.35, P < .008). Parent rating was a marginal indicator of global intellect only. CONCLUSION The brief neurocognitive screening was a better predictor of child functioning than specific parent rating. This brief measure, which can be completed in 30 minutes, is a practical and reliable method to identify cancer survivors in need of further neurocognitive follow-up.

Synovial sarcoma in children: surgical lessons from a single institution and review of the literature

BACKGROUND Synovial sarcomas are malignant high-grade, soft-tissue neoplasms that account for 7% to 8% of all malignant soft-tissue tumors and are the most common nonrhabdomyosarcoma soft-tissue sarcomas in pediatric patients. STUDY DESIGN A retrospective review of the records of children younger than 17 years with synovial sarcoma treated at the University of Texas MD Anderson Cancer Center from 1966 until 1999 was undertaken. Primary site, tumor size, tumor margins, surgical treatment, adjuvant therapy, local and distant recurrence, and survival were recorded for 42 patients. Overall survival (OS) and progression-free survival (PFS) rates were calculated by the Kaplan-Meier method. The PFS and OS comparisons were performed using the log-rank test. RESULTS Forty-four patients were identified, but two patients were excluded because of incomplete records. The median followup duration for the 42 patients was 8.8 years (range 0.2 to 22.4 years). The 5-year progression-free survival and overall survival rates were 75.6% and 87.7%, respectively. Eleven patients were dead and four others had progressed but were alive without evidence of disease after further therapy. Intergroup Rhabdomyosarcoma Study (IRS) grouping and tumor invasiveness were found to be significant prognostic indicators (p < 0.01 and p = 0.02, respectively). Patients with initial gross total resection (IRS Groups I and II) and noninvasive tumors (T1) were most likely to have prolonged PFS and OS. Patients with small tumors (<5 cm) (p = 0.09) had better PFS and OS. Adjuvant radiation therapy appeared to be of benefit, and chemotherapy did not seem to impact PFS or OS. Tumors > or = 5 cm are associated with increased risk of local recurrence and distant metastases. CONCLUSIONS Complete resection with clear, yet not necessarily large, margins remains the treatment of choice for synovial sarcoma in children. Adjuvant radiation therapy should possibly be considered in patients with clear margins (IRS Group I) and in patients with microscopic residual tumor (IRS Group II). Chemotherapy did not seem to impact PFS or OS. Lymph nodes should be evaluated for local regional disease.

Survival Prediction in Patients With Glioblastoma Multiforme by Human Telomerase Genetic Variation

PURPOSE Glioblastoma multiforme (GBM) is the most common and aggressive glioma with the poorest survival. Use of biomarkers for screening patients with GBM may be used to modify treatments and improve outcomes. The level of human telomerase (hTERT) expression is an independent predictor of outcome of many cancers, and a functional variant of hTERT MNS16A (shorter tandem repeats or short [S] allele) is associated with increased hTERT mRNA expression. We investigated whether hTERT MNS16A variant genotype predicted survival in GBM patients. PATIENTS AND METHODS We genotyped hTERT MNS16A in 299 GBM patients using polymerase chain reaction and determined hTERT genotype by classifying the DNA band of 243 or 272 base pairs (bp) as S allele and 302 or 333 bp as long (L) allele. We compared overall survival using Kaplan-Meier estimates and equality of survival distributions using the log-rank test, and we computed univariate and multivariate Cox proportional hazards models to estimate the effects of selected variables. RESULTS Overall survival differed significantly by hTERT MNS16A genotype, with median survivals of 25.1, 14.7, and 14.6 months for the SS, SL, and LL genotypes, respectively. Compared with the SS genotype, the hazard ratios for the SL and LL genotypes were 1.69 and 1.87, respectively, after adjustment for other factors. Multivariate Cox regression analysis showed an independent statistically significant association between the hTERT MNS16A variant genotype and outcome. CONCLUSION A functional hTERT MNS16A genotype is a potential biomarker for assessment of survival outcome of GBM. Larger studies are needed to verify these findings.

Aurora A is a negative prognostic factor and a new therapeutic target in human neuroblastoma

We studied expression of the Aurora A gene and its clinical significance in a cohort of neuroblastoma patients. In addition, we investigated the antitumor activity of MLN8054, a novel small-molecule inhibitor of Aurora A kinase, on cultured NB cell lines in vitro. Aurora A mRNA expression was assessed by quantitative real-time PCR in tumor tissue specimens from 67 patients at diagnosis and in 9 human neuroblastoma cell lines. Western blot assays for Aurora A protein were done on tumor tissue of 53 patients. The results were correlated with various prognostic factors of neuroblastoma. Aurora A mRNA and protein expression were identified in 9 of 9 neuroblastoma cell lines. Overexpression of Aurora A mRNA in neuroblastoma tumor tissue is associated with high risk (P = 0.019), high-stage (International Neuroblastoma Staging System III and IV) tumors (P = 0.007), unfavorable histology (P = 0.007), MYCN amplification (P = 0.017), disease relapse (P = 0.019), and decreased progression-free survival (P < 0.0001) but not correlated with the age at diagnosis (P = 0.877). Similarly, Aurora A protein expression also significantly correlated with high risk (P = 0.011), high stage (P = 0.0028), unfavorable histology (P = 0.0006), MYCN amplification (P = 0.0029), and disease relapse (P = 0.044). Small interfering RNA–mediated knockdown of the endogenous Aurora A gene causes a proliferation defect and enhances chemosensitivity in human neuroblastoma cell lines. In support of these observations, the Aurora A kinase inhibitor, MLN8054, markedly inhibited growth of cultured neuroblastoma cell lines through an apoptosis-dependent pathway. Overexpression of Aurora A is associated with disease progression in neuroblastoma. Inhibition of this kinase is a promising modality for neuroblastoma treatment. [Mol Cancer Ther 2009;8(8):2461–9]

Ototoxicity After Intensity-Modulated Radiation Therapy and Cisplatin-Based Chemotherapy in Children With Medulloblastoma

PURPOSE To report the incidence of Pediatric Oncology Group (POG) Grade 3 or 4 ototoxicity in a cohort of patients treated with craniospinal irradiation (CSI) followed by posterior fossa (PF) and/or tumor bed (TB) boost using intensity-modulated radiation therapy (IMRT). METHODS AND MATERIALS From 1998 to 2006, 44 patients with medulloblastoma were treated with CSI followed by IMRT to the PF and/or TB and cisplatin-based chemotherapy. Patients with standard-risk disease were treated with 18 to 23.4 Gy CSI followed by either a (1) PF boost to 36 Gy and TB boost to 54 to 55.8 Gy or (2) TB boost to 55.8 Gy. Patients with high-risk disease received 36 to 39.6 Gy CSI followed by a (1) PF boost to 54 to 55.8 Gy, (2) PF boost to 45 Gy and TB boost to 55.8 Gy, or (3) TB boost to 55.8 Gy. Median audiogram follow-up was 41 months (range, 11-92.4 months). RESULTS POG Grade Ototoxicity 0, 1, 2, 3. and 4 was found in 29, 32, 11, 13. and 3 ears. respectively, with POG Grade 3 or 4 accounting for 18.2% of cases. There was a statistically significant difference in mean radiation dose (D(mean)) cochlea according to degree of ototoxicity, with D(mean) cochlea increasing with severity of hearing loss (p = 0.027). CONCLUSIONS Severe ototoxicity was seen in 18.2% of ears in children treated with IMRT boost and cisplatin-based chemotherapy. Increasing dose to the cochlea was associated with increasing severity of hearing loss.

BCOR-CCNB3 fusions are frequent in undifferentiated sarcomas of male children.

The BCOR–CCNB3 fusion gene, resulting from a chromosome X paracentric inversion, was recently described in translocation-negative ‘Ewing-like’ sarcomas arising in bone and soft tissue. Genetic subclassification of undifferentiated unclassified sarcomas may potentially offer markers for reproducible diagnosis and substrates for therapy. Using whole transcriptome paired-end RNA sequencing (RNA-seq) we unexpectedly identified BCOR–CCNB3 fusion transcripts in an undifferentiated spindle-cell sarcoma. RNA-seq results were confirmed through direct RT-PCR of tumor RNA and cloning of the genomic breakpoints from tumor DNA. Five additional undifferentiated sarcomas with BCOR–CCNB3 fusions were identified in a series of 42 pediatric and adult unclassified sarcomas. Genomic breakpoint analysis demonstrated unique breakpoint locations in each case at the DNA level even though the resulting fusion mRNA was identical in all cases. All patients with BCOR–CCNB3 sarcoma were males diagnosed in mid childhood (7–13 years of age). Tumors were equally distributed between axial and extra-axial locations. Five of the six tumors were soft-tissue lesions with either predominant spindle-cell morphology or spindle-cell areas interspersed with ovoid to round cells. CCNB3 immunohistochemistry showed strong nuclear positivity in five tumors before oncologic therapy, but was patchy to negative in post-treatment tumor samples. An RT-PCR assay developed to detect the fusion transcript in archival formalin-fixed tissue was positive in all six cases, with high sensitivity and specificity in both pre- and post-treated samples. This study adds to recent reports on the clinicopathologic spectrum of BCOR–CCNB3 fusion-positive sarcomas, a newly emerging entity within the undifferentiated unclassified sarcoma category and describes a simple RT-PCR assay that in conjunction with CCNB3 immunohistochemistry can be useful in diagnosing these tumors.

A meta‐analysis of MTHFR C677T and A1298C polymorphisms and risk of acute lymphoblastic leukemia in children

Methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms have been implicated in childhood acute lymphoblastic leukemia (ALL) risk, but previously published studies were inconsistent and recent meta‐analyses were not adequate.

Imaging Changes in Pediatric Intracranial Ependymoma Patients Treated With Proton Beam Radiation Therapy Compared to Intensity Modulated Radiation Therapy

PURPOSE The clinical significance of magnetic resonance imaging (MRI) changes after radiation therapy (RT) in children with ependymoma is not well defined. We compared imaging changes following proton beam radiation therapy (PBRT) to those after photon-based intensity modulated RT (IMRT). METHODS AND MATERIALS Seventy-two patients with nonmetastatic intracranial ependymoma who received postoperative RT (37 PBRT, 35 IMRT) were analyzed retrospectively. MRI images were reviewed by 2 neuroradiologists. RESULTS Sixteen PBRT patients (43%) developed postradiation MRI changes at 3.8 months (median) with resolution by 6.1 months. Six IMRT patients (17%) developed changes at 5.3 months (median) with 8.3 months to resolution. Mean age at radiation was 4.4 and 6.9 years for PBRT and IMRT, respectively (P = .06). Age at diagnosis (>3 years) and time of radiation (≥3 years) was associated with fewer imaging changes on univariate analysis (odds ratio [OR]: 0.35, P = .048; OR: 0.36, P = .05). PBRT (compared to IMRT) was associated with more frequent imaging changes, both on univariate (OR: 3.68, P = .019) and multivariate (OR: 3.89, P = .024) analyses. Seven (3 IMRT, 4 PBRT) of 22 patients with changes had symptoms requiring intervention. Most patients were treated with steroids; some PBRT patients also received bevacizumab and hyperbaric oxygen therapy. None of the IMRT patients had lasting deficits, but 2 patients died from recurrent disease. Three PBRT patients had persistent neurological deficits, and 1 child died secondarily to complications from radiation necrosis. CONCLUSIONS Postradiation MRI changes are more common with PBRT and in patients less than 3 years of age at diagnosis and treatment. It is difficult to predict causes for development of imaging changes that progress to clinical significance. These changes are usually self-limiting, but some require medical intervention, especially those involving the brainstem.

Glutathione S-transferase M1 and T1 polymorphisms may predict adverse effects after therapy in children with medulloblastoma.

Glutathione S-transferases (GSTs) are polymorphic enzymes that catalyze the glutathione conjugation of alkylating agents, platinum compounds, and free radicals formed by radiation used to treat medulloblastoma. We hypothesized that GST polymorphisms may be responsible, in part, for individual differences in toxicity and responses in pediatric medulloblastoma. We investigated the relationship between GSTM1 and GSTT1 polymorphisms and survival and toxicity in 42 children with medulloblastoma diagnosed and treated at the Texas Childrens Cancer Center. We conducted Kaplan-Meier analyses to determine if the GST polymorphisms were related to progression-free survival (PFS) and performed logistic regression to explore associations between GST polymorphisms and occurrence of grade 3 or greater (> or =Gr 3) myelosuppression, ototoxicity, nephrotoxicity, neurotoxicity, and intellectual impairment. Patients with at least one null genotype had a 4.3 (95% confidence interval, 1.1-16.8), 3.7 (1-13.6), and 6.4 (1.2-34) times increased risk for any > or =Gr 3 toxicity, any > or =Gr 3 toxicity excluding peripheral neuropathy, and any > or =Gr 3 toxicity requiring omission or cessation of chemotherapy, respectively. Compared with all others, patients with at least one null genotype had, on average, 27.2 (p x= 0.0002), 29 (p = 0.0004), and 21.7 (p = 0.002) lower full-scale, performance, and verbal intelligence quotient (IQ) scores, respectively. GSTM1 and GSTT1 polymorphisms may predict adverse events, including cognitive impairment after therapy, in patients with medulloblastoma. A larger study to validate these findings is under way.