Abstract Background: In B-CLL, the observation of interphase cells with hemizygous D13S319 deletion at 13q14 (13q-x1) as a sole anomaly in blood is widely considered a favorable prognosis. The observation of cells with 11q-, +12 or 17p- has been associated with a relatively poor prognosis. Over the past 1.5 yrs, 16.2% (174/1,076) of patients (pts) referred for fluorescence in situ hybridization (FISH) testing for B-CLL in our clinical practice had a clone with homozygous D13S319 deletion (13q-x2), but the prognostic significance of this observation is poorly understood. Moreover, 39.3% (142/361) of pts with unfavorable FISH anomalies have 13q-x1 and/or 13q-x2 and the clinical significance of this observation is also unknown. Thus, we investigated pts with 13q- (with or without other chromosome anomalies) to establish the relative clinical significance of 13q- in B-CLL. Methods: We studied 333 pts with B-CLL sampled between 9/1999 and 6/2004 who had FISH performed on interphase nuclei from blood. The FISH probe set was designed to detect 6q-, 11q-, +12, 13q-, 17p-, and translocations involving IgH at 14q32. We classified pts into four groups: 13q-x1 only (group 1), 13q-x1 and 13q-x2 only (group 2), 13q-x2 only (group 3) and 13q-x1 and/or 13q-x2 plus other FISH anomalies (group 4). FISH groups were compared with gender, age, Rai stage, treatment status, time to treatment, CD38 and IgVH mutation. Results: Of the 333 pts, 171 (51.3%) had a 13q-: 71 were in group 1, 25 in group 2, 26 in group 3 and 49 in group 4. %CD38+ differed significantly across FISH groups; in pairwise analyses, the proportion of pts with >30% CD38+ was significantly greater for pts in group 4 vs. group 3 (p=0.0015) although no significant differences were observed for group 3 vs. group 1 or vs. group 2. Pts in group 3 were not significantly different from other FISH groups for Rai stage, IgVH mutation or gender. The median percentage of abnormal nuclei for pts with group 1 was 54.5% vs. 79.5% for pts in group 4 (p<0.0001). The median percent abnormal nuclei for pts in groups 3 and 2 was 72.5% and 68.5%, respectively. Median % abnormal nuclei for group 3 was not significantly different than the other FISH groups. Treatment status was available on 147 pts, where the proportion of pts who had treatment in each group was as follows: group 1, 15/66; group 2, 2/22; group 3, 4/21; and group 4, 9/38. Due to limited sample size and heavy censoring, any analysis on time to treatment is preliminary; however, these early analyses suggest group 4 pts have a lower median time to treatment (9 yrs) compared to groups 3 and 1 (12.3 and 13 yrs, respectively). Conclusions: This study has generated new information about the 13q- anomaly in B-CLL. First, known prognostic markers for B-CLL pts with 13q-x2 are not significantly different than for pts with 13q-x1 or 13q-x1/13q-x2. Second, 13q-x1 and/or 13q-x2 occurring with other unfavorable FISH anomalies have an unfavorable prognosis; i.e. potential benefits of 13q- are trumped when it is observed with unfavorable FISH anomalies. Thus, patients with any form of 13q- alone may have indolent disease while patients with 13q- and unfavorable FISH anomalies should be considered to be in a more aggressive phase.
Interphase Fluorescence In Situ Hybridization (FISH) with an IgH Probe Is Important in the Management of Patients with a Clinical Diagnosis of Chronic Lymphocytic Leukemia (CLL).
Abstract Genetic analysis has an increasing role in the diagnosis, classification, and management of patients with CLL. Although translocations involving the IgH locus are well characterized in B-cell malignancies such as follicular cell lymphoma, their frequency and significance in CLL are less well defined. We studied a series of patients with a clinical diagnosis of CLL using a FISH probe set including IgH. Methods: FISH was performed on blood using a DNA probe set designed to detect common chromosome anomalies associated with CLL and translocations involving IgH. Patients with an IgH abnormality were further studied using FISH probes sets for IgH and cyclin D1, BCL-2, BCL-3, BCL-6, BCL-11a, c-MYC, MALT-1, c-MAF, FGFR-3 or PAX-5. The clinical presentation, pathology, and flow cytometric immunophenotype was reviewed in patients with various translocations involving IgH. Results: Between 1/1/03 and 6/15/04, samples from 1032 patients with a clinical diagnosis of CLL were analyzed by FISH. Of these, 76 patients (7%) had translocations involving the IgH locus. Sixty one patients had a single translocation partner gene (cyclin D1 45%, BCL-2 24%, BCL-3 8%, c-MYC 2.5%, or BCL-11a 1.3%). Two patients had two independent clones (cyclin D1 and BCL-2; BCL-3 and BCL-11a). In 13 pts (17%) we could not identify the translocation partner. Thirty five (46%) of the 76 patients with IgH translocations had been seen at Mayo Clinic Rochester and had clinical and laboratory data for detailed review. Among these 35 patients, 16 (45%) had fusion of IgH and cyclin D1 and were diagnosed with mantle cell lymphoma (MCL). The immunophenotype of the monoclonal B cells was typical of MCL (CD5+, CD23-) in 6 patients and typical of CLL (CD5+, CD23+) in 4 patients. Six MCL patients had non-diagnostic immunophenotypes: CD5-, CD 23+ (n = 3) and CD5-, CD23- (n = 3). Twelve (34%) of the 35 patients had the IGH/BCL-2 fusion gene. Of these, 3 patients had leukemic phase follicular lymphoma, one had both CLL and MCL, and 8 had the diagnostic immunophenotype of CLL. The remaining 7 patients (19%) had a variety of translocation partners: BCL-3 (n = 1), BCL-3 and BCL-11a (n = 1), c-MYC (n = 2), and unknown (n = 3). The patients with a translocation involving BCL-3 had a typical CLL immunophenotype. Discussion: The IgH FISH probe detected a molecular defect in 7% of patients with a circulating monoclonal B cell population. In patients with a CLL immunophenotype, use of the IgH probe identified the IgH/cyclin D1 translocation characteristic of MCL in 4 patients, a finding of major clinical significance. Interestingly, after exclusion of MCL patients, more than 4% patients with CLL had other translocations involving IgH, a proportion comparable with other better defined chromosomal abnormalities in CLL. Although IgH/BCL-2 translocation is usually associated with follicular lymphoma, we identified 8 patients with CLL and this translocation. Translocations involving BCL-3 had been described before in CLL with an “atypical” immunophenotype. In contrast both of our patients with BCL-3 had typical phenotypes. Translocations involving IgH and BCL-11a have not been previously described. We conclude that FISH studies using the IgH probe improve the precision of diagnosis in CLL and could also have prognostic value.
Efficacy of Conventional Cytogenetics and FISH for EGR1 To Detect Deletion 5q in Hematological Disorders and To Assess Response to Treatment with Lenalidomide.
Abstract Background: In 2006 Lenalidomide received FDA approval for myelodysplasia (MDS) with interstitial deletion 5q [del(5q)] based on conventional cytogenetic (CC) results before and after treatment. In clinical practice, FISH studies of interphase nuclei with probes for EGR1 are widely used to detect del(5q), but it is not known whether this method has similar efficacy as CC. Thus, we compared CC and FISH results for various forms of del(5q). Methods: We selected 145 patients (pts) in our cytogenetic database with del(5q). These pts had various forms of del(5q) and were representative of our clinical practice. This series included 9 pts with MDS that were studied before and after treatment with Lenalidomide. CC studies were done using standard procedures to analyze 20 metaphases from bone marrow. FISH studies were done on the same specimens using stored left-over cells and standard procedures for EGR1 (5q31.2) and D5S23/D5S721 (5p15.2). The cutoff for del(5q) for FISH was <6.0% based on 200 nuclei. Results: Among 145 pts, 104 were referred for MDS, 9 acute myeloid leukemia, 9 lymphoproliferative disorders, 7 myeloproliferative disorders and 16 without clinical information. A total of 116 pts had breakpoints at del(5)(q13q33), 17 del(5)(q15q33), 8 del(5)(q11.2~q31q31~q35), 3 del(5)(q22q33) and 1 del(5)(q13q22). Del(5q) was detected in 144 pts by both CC and FISH. One pt had del(5)(q13q22) in 20/20 metaphases but was normal by FISH. Percent abnormal cells by FISH was lower in 135/145 pts compared to CC (mean difference 22.5 ± 19.6, range −42 to 98). For 9 pts with MDS, 29 specimens were collected before and after treatment with Lenalidomide: 7 achieved complete cytogenetic remission (four relapsed) and 2 showed a decrease in percent abnormal metaphases. Results of CC and FISH for these 9 pts were concordant for detection of del(5q) and trend of tumor burden due to treatment for 28/29 specimens. The discordant specimen was collected 222 days after treatment; results of CC were normal but FISH was abnormal in 19% of nuclei. Among the 29 specimens, percent abnormal cells by FISH was lower than CC in 27 (mean difference 13.9% ± 22.5, range −19.0 to 73.5). Each of the 9 treated pts had only del(5q) prior to treatment, and was detected by both FISH and CC. After treatment, FISH did not detect a separate cytogenetic clone involving deletion 20q without del(5q) in 2 pts nor did it identify development of other anomalies in 3 pts. Conclusions: Results of CC and FISH were mostly concordant, but differed in 4 respects. First, 1/145 pts was normal by FISH but had del(5q) by CC. This pt had unusual breakpoints that did not result in loss of EGR1. Second, percentage of cells with del(5q) was usually lower by FISH than CC. This observation is likely related to a different mitotic rate of cells with del(5q) versus normal cells. Third, 1 specimen was abnormal by FISH but normal by CC after treatment, but 2 subsequent specimens were concordant. This discrepancy was likely due to interference of mitosis of del(5q) cells and residual non-proliferating disease. Fourth, 2 treated pts developed a separate cytogenetic clone without del(5q) and 3 developed other anomalies that could not be detected by FISH. We believe FISH for EGR1 is useful in clinical practice, but not a substitute for CC.
Syk Tyrosine Kinase Is Overexpressed in the Majority of Peripheral T- and NK-Cell Lymphomas, and Represents a Potential Therapeutic Target.
Abstract Peripheral T- and NK-cell lymphomas (PTCLs) are fatal in the majority of patients, and conventional chemotherapy is minimally effective. Targeted inhibition of tyrosine kinases (TKs) might be a useful treatment strategy, but TK overexpression by PTCLs has not been well characterized (except ALK). Recently a novel translocation t(5;9) fusing the ITK and SYK genes was reported in a subset of unspecified-type PTCLs, associated with high SYK gene expression and Syk protein positivity. Syk is a non-receptor TK important in immunoreceptor signal transduction, providing proliferation and survival signals in a variety of hematopoietic cells. Syk is absent or expressed at very low levels in most normal post-thymic T cells, where this signal transduction role is fulfilled by ZAP70. Since Syk TK inhibitors are now in clinical trials for other diseases, we sought to determine the incidence of t(5;9) and Syk overexpression in PTCL. Tissue microarrays were constructed using triplicate cores from paraffin-embedded tissue blocks. Cases were studied using fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC). Additional studies were performed using flow cytometry and Western blot. There were 141 PTCLs, including 35 angioimmunoblastic, 66 unspecified, 21 anaplastic large cell, 2 enteropathy-associated, 5 hepatosplenic, 5 extranodal NK/T, and 7 other. No evidence of t(5;9) was identified by FISH in 86 informative cases. Normal T-cell subsets from peripheral blood, spleen, and lymph node were negative for Syk by IHC, flow cytometry, and Western blot. Syk was positive by immunohistochemistry in 133 of 141 (94%) PTCLs. All 8 Syk negative cases were extranodal, cytotoxic PTCLs. Western blot on frozen tissue correlated with IHC results in paraffin. All 4 Syk-positive cases tested showed phosphorylation of tyrosine residues 525/526, known to be required for Syk activation. We conclude that Syk is overexpressed in most PTCLs, including the vast majority of nodal cases. Syk may substitute for ZAP70 in these tumors and provide ongoing proliferation and survival signaling. The overexpression of Syk and phosphorylation of its Y525/526 residues suggest Syk may be a suitable target for pharmacologic TK inhibition as a treatment option for patients with PTCL.
Validation of a genomic-clinical classifier model for predicting clinical recurrence of patients with localized prostate cancer in a high-risk population.
175 Background: The efficient delivery of adjuvant and salvage therapy after radical prostatectomy in patients with prostate cancer is hampered by a lack of biomarkers to assess the risk of clinically significant recurrence and progression. Methods: Mayo Clinic Radical Prostatectomy Registry (RP) patient specimens were selected from a case-control cohort with 14 years median follow-up for training and initial validation of an expression biomarker genomic classifier (GC). An independent, blinded case-cohort study of high-risk RP subjects was used to validate GC, comparing the performance of GC to a multivariate logistic regression clinical model (CM) and GC combined with clinical variables (genomic-clinical classifier, GCC) for predicting clinical recurrence (defined as positive bone or CT scan within 5 years after biochemical recurrence). The concordance index (c-index) and Cox model were used to evaluate discrimination and estimate the risk of clinical recurrence. Results: In the training subset (n=359), both GC and GCC had a c-index of 0.90 whereas CM had a c-index of 0.76. In the internal validation set (n=186), GC and GCC had a c-index of 0.76 and 0.75, while CM had a c-index of 0.69. In an independent high-risk study (n=219), GC and GCC had a c-index of 0.77 and 0.76, while CM had a c-index of 0.68. In subset analysis of Gleason score 7 patients within the high-risk group, GC and GCC showed improved discrimination with c-index of 0.78 and 0.76, respectively compared to 0.70 for CM. In the high-risk group, the risk of recurrence by GC model score quartiles at 5 years after RP was estimated at 1%, 5%, 5% and 18%. Conclusions: The GC model shows improved performance over CM in the prediction of clinical recurrence in a high-risk cohort and in subset analysis of Gleason score 7 patients. The addition of clinical variables to the GC model did not significantly contribute to classifier performance in patients with high-risk features. We are further testing the performance of the GC and GCC models and their usefulness in guiding decision-making (e.g., for the adjuvant therapy setting) in additional studies of prostate cancer clinical risk groups.
Abstract 4207: The germline rs55705857 risk allele is not preferentially gained in gliomas with 8q24 duplication.
Abstract Background: Gliomas are primary malignant brain tumors with significant morbidity and mortality. Single nucleotide polymorphisms (SNPs) mapped to 8q24 have been shown to be associated with glioma development. Recently, we identified seven SNPs (through tag SNP genotyping/imputation, pooled next-generation sequencing using long-range PCR, and validation SNP genotyping) that are highly associated with the risk of developing glioma. After stratifying by histologic and tumor subtype, one SNP, rs55705857, in the 8q24.21 region near CCDC26 was significantly associated with oligodendroglial tumors and IDH mutated astrocytic gliomas with high odds ratios (ORs ∼6.0) (Jenkins et al. Nature Genet. 44:1122;2012). By array comparative genomic hybridization (aCGH), a significant proportion of oligodendroglial tumors and IDH mutated astrocytomas have been shown to duplicate 8q24 (Kitange et al., Genes Chr Cancer 42:68;2005; Nousmehr et al. Cancer Cell 17:510;2010). We were interested in learning if the germline risk allele of rs55705857 is associated with gliomas that duplicate 8q24. We were also interested in learning if the risk allele is preferentially gained in gliomas that duplicate 8q24. Methods: We performed aCGH on 217 tumor samples. rs55705857 germline genotype was available on 120 of the patients; of which 30 carried the risk (G) allele. In addition, we sequenced the rs55805857 region in 48 gliomas, 15 of which exhibited gain or duplication of chromosome 8, 8q, or 8q24. The ratio of the Sanger-sequencing peak heights at and around rs55705857 was used to determine which allele (risk or wild-type) was gained. Results: All 15 duplications included rs55705857 and the immediately adjacent regions. Of the 30 patients who carried the germline risk (G) allele for rs55707857, 8 (26.7%) exhibited duplication of 8q24 upon aCGH analysis of their glioma. Of the 90 patients who only carried the wild-type (A) allele, 7 (7.5%) exhibited duplications of 8q24 upon aCGH analysis of their glioma. This difference in proportion is statistically significant (p=0.024, Fischer exact test). Of the 15 tumors with duplication of 8q24, 8 came from patients who were germline rs55705857 heterozygotes (AG). Of these 8 germline heterozygotes with duplication of 8q24, 4 gained the risk (G) allele, 2 gained the wild-type (A) allele and 2 exhibited gain of both alleles in their tumor specimens. Conclusions: While the results require replication, our data suggest that carrying the risk allele for rs55705857 predisposes to the development of gliomas that subsequently duplicate 8q24. However, gliomas with duplication of 8q24 do not preferentially gain the risk rs55705857 allele. This result implies that, while the duplication always includes the rs55705857 region, the risk allele or region is not the direct target of the duplication. Citation Format: Amanda L. Rynearson, Kirsten A. Schowalter, Stephanie R. Fink, Thomas M. Kollmeyer, Chandralekha Halder, Gobinda Sarkar, Alissa A. Caron, Rachel A. Pauley, Daniel H. Lachance, Brian Patrick O'Neill, Robert B. Jenkins. The germline rs55705857 risk allele is not preferentially gained in gliomas with 8q24 duplication. [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 4207. doi:10.1158/1538-7445.AM2013-4207
Tumorgrafts as
In Vivo
Surrogates for Women with Ovarian Cancer
Abstract Glioblastoma multiforme (GBM) is the most common and highly malignant primary brain tumor in adults with a median survival just over 1 year, and novel therapies are urgently needed. Deregulation of the p16 (INK4A)-CDK4/6-pRb pathway are commonly found in human GBM patients and selective inhibitors of CDK4/6 may be specifically useful to suppress proliferation associated with these alterations. PD0332991 is an orally active small molecule that specifically inhibits CDK4 and CDK6. Therefore, the efficacy of PD0332991 was evaluated in the Mayo panel of primary GBM xenograft lines using short-term explant cultures. We hypothesized that expression of p15 and/or p16, endogenous inhibitors of CDK4/6 activity, would suppress the response of GBM tumors to PD0332991 treatment. To test this hypothesis, 2 GBM xenograft cell lines with wild-type p16/p15 levels (GBM5 and 28) and 2 lines without detectable p16/p15 levels (GBM22 and 43) were selected for further analysis. Tumor cells were treated with graded concentrations (10 nanoM to1 microM) of PD0332991 for 5 days and subjected to CyQUANT cell proliferation assays. Consistent with our hypothesis, treatment with 1 microM PD0332991 effectively inhibited cell proliferation to 56.6±3.5% (P<0.001) and 44.3±3.4% (P<0.001) of control in GBM22 and GBM43 cells respectively, but did not affect cell proliferation in GBM5 and GBM28 cells (98.7±15.6% and 101.8±12.0% of control, respectively). In addition, 1 microM PD0332991 induced G1-phase cell cycle arrest in GBM22 (treated 79.7±0.8% vs. control 63.4±0.5% of cells in G1 phase, P<0.001) and GBM43 (treated 70.6±1.1% vs. control 48.9±4.6% of cells in G1 phase, P<0.001) but not in GBM5 and GBM28 (treated 52.3±2.7% vs. control 54.0±5.1%, treated 52.4±4.7% vs. control 54.6±2.6%, respectively). The status of p15 and p16 was confirmed by RT-PCR, which demonstrated readily detectable expression of p15 and p16 in GBM5 and GBM28, but not in GBM22 and GBM43 cells. Additional comparative genomic hybridization (CGH) data showed that CDKN2A and 2B (genes encode for p16 and p15 respectively) are homozygously deleted in GBM22 and 43, hemizygously deleted in GBM5 and normal in GBM28. We also examined the status of CDK4, CDK6, pRb and other molecules in the p16-CDK4/6-pRb pathway by Western, RT-PCR and CGH in these GBM lines and the data will be presented. We are now testing whether shRNA knockdown and/or re-expression of p15/p16 in the relevant cell lines alters their responsiveness to PD0332991. In conclusion, CDK4/6 inhibitor PD0332991 inhibits cell proliferation and induces G1 cell cycle arrest in p15/p16- null GBM tumors, but is less effective in p15/p16 expressing tumors. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C191.
Primary Central Nervous System Lymphomas: A Validation Study of Array-Based Comparative Genomic Hybridization in Formalin-Fixed Paraffin-Embedded Tumor Specimens
Abstract Multiple genome-wide association studies have identified several susceptibility variants for colon cancer at 8q24. However, the functional roles of these variants have yet to be elucidated. Here, we evaluated the potential role of these markers in tumor progression and examined association with commonly observed structural abnormalities in this region, c-MYC amplification and chromosome fragility at FRA8C and FRA8D. We first replicated the previously reported association by testing 1,178 cases and 1,009 clinic-based controls with eight markers localized to three specific regions at 8q24. We observed significant associations with colon cancer risk with markers rs13254738 (ordinal odds ratio, 0.82; 95% confidence interval, 0.072-0.94; Ptrend = 0.0037) and rs6983267 (ordinal odds ratio, 1.17; 95% confidence interval, 1.03-1.32, Ptrend = 0.013). Survival analysis was done using a separate set of 460 cases to evaluate the clinical significance of these markers. Overall, univariate analysis did not detect survival differences for any of the markers. We also tested a subset of the 460 cases (n = 380) for structural abnormalities at or near the c-MYC locus using fluorescence in situ hybridization analysis. Furthermore, we evaluated a small number of cases homozygous for the rs6983267 alleles to test for differences in fragile site induction. None of the 8q markers correlated with amplification at the c-MYC locus as detected by fluorescence in situ hybridization, and no clear pattern of breakage was observed at the FRA8C and FRA8D sites. In this study, we confirm the association for several single nucleotide polymorphisms at 8q24 in colon cancer but have not detected any structural role relating to c-MYC amplification or chromosomal fragility. Finally, these risk alleles do not seem to be associated with survival. (Cancer Epidemiol Biomarkers Prev 2009;18(9):2492–500)