Fluorescence in-situ hybridisation for TP63 rearrangements in T cell lymphomas: single-site experience of 470 patients and implications for clinical testing.

AIMS: The aims of this study were to review our 5-year experience with clinical FISH testing for TP63 rearrangements using both TP63 break-apart (BAP) and TBL1XR1/TP63 dual-fusion (D-FISH) probes to evaluate the frequency of TP63 rearrangements and the distribution of TBL1XR1 vs. alternate partner loci, and to assess whether both probe sets are necessary in all cases undergoing FISH testing. METHODS AND RESULTS: A retrospective review of the Mayo Clinic cytogenetic database identified 470 patients evaluated by FISH testing for TP63 rearrangements in formalin-fixed paraffin-embedded (FFPE) tissue using both BAP and D-FISH probes. Of these, 25 (5.3%) had TP63 rearrangements. All samples were being investigated for anaplastic large-cell lymphoma or other T cell lymphoma subtypes. A TBL1XR1 partner was identified by D-FISH in 12 (48%) of 25 cases. All cases positive by TBL1XR1/TP63 D-FISH were also positive by TP63 BAP FISH. CONCLUSION: This is the largest series of TP63 rearrangements to date. The frequency of positive results among cases referred to a large reference laboratory for TP63 FISH testing was 5.3%. Approximately half of TP63 rearrangements have a TBL1XR1 partner. TP63 BAP FISH testing is sufficient for up-front testing of FFPE tissue samples. However, because of the genomic proximity of the TP63 and TBL1XR1 loci, we recommend reflex TBL1XR1/TP63 D-FISH testing in positive and equivocal cases.

Integrated mate-pair and RNA sequencing identifies novel, targetable gene fusions in peripheral T-cell lymphoma.

Peripheral T-cell lymphomas (PTCLs) represent a heterogeneous group of T-cell malignancies that generally demonstrate aggressive clinical behavior, often are refractory to standard therapy, and remain significantly understudied. The most common World Health Organization subtype is PTCL, not otherwise specified (NOS), essentially a "wastebasket" category because of inadequate understanding to assign cases to a more specific diagnostic entity. Identification of novel fusion genes has contributed significantly to improving the classification, biologic understanding, and therapeutic targeting of PTCLs. Here, we integrated mate-pair DNA and RNA next-generation sequencing to identify chromosomal rearrangements encoding expressed fusion transcripts in PTCL, NOS. Two of 11 cases had novel fusions involving VAV1, encoding a truncated form of the VAV1 guanine nucleotide exchange factor important in T-cell receptor signaling. Fluorescence in situ hybridization studies identified VAV1 rearrangements in 10 of 148 PTCLs (7%). These were observed exclusively in PTCL, NOS (11%) and anaplastic large cell lymphoma (11%). In vitro, ectopic expression of a VAV1 fusion promoted cell growth and migration in a RAC1-dependent manner. This growth was inhibited by azathioprine, a clinically available RAC1 inhibitor. We also identified novel kinase gene fusions, ITK-FER and IKZF2-ERBB4, as candidate therapeutic targets that show similarities to known recurrent oncogenic ITK-SYK fusions and ERBB4 transcript variants in PTCLs, respectively. Additional novel and potentially clinically relevant fusions also were discovered. Together, these findings identify VAV1 fusions as recurrent and targetable events in PTCLs and highlight the potential for clinical sequencing to guide individualized therapy approaches for this group of aggressive malignancies.

Gastroblastoma harbors a recurrent somatic MALAT1-GLI1 fusion gene.

Gastroblastoma is a rare distinctive biphasic tumor of the stomach. The molecular biology of gastroblastoma has not been studied, and no affirmative diagnostic markers have been developed. We retrieved two gastroblastomas from the consultation practices of the authors and performed transcriptome sequencing on formalin-fixed paraffin-embedded tissue. Recurrent predicted fusion genes were validated at genomic and RNA levels. The presence of the fusion gene was confirmed on two additional paraffin-embedded cases of gastroblastoma. Control cases of histologic mimics (biphasic synovial sarcoma, leiomyoma, leiomyosarcoma, desmoid-type fibromatosis, EWSR1-FLI1-positive Ewing sarcoma, Wilms' tumor, gastrointestinal stromal tumor, plexiform fibromyxoma, Sonic hedgehog-type medulloblastomas, and normal gastric mucosa and muscularis propria were also analyzed. The gastroblastomas affected two males and two females aged 9-56 years. Transcriptome sequencing identified recurrent somatic MALAT1-GLI1 fusion genes, which were predicted to retain the key domains of GLI1. The MALAT1-GLI1 fusion gene was validated by break-apart and dual-fusion FISH and RT-PCR. The additional two gastroblastomas were also positive for the MALAT1-GLI1 fusion gene. None of the other control cases harbored MALAT1-GLI1. Overexpression of GLI1 in the cases of gastroblastomas was confirmed at RNA and protein levels. Pathway analysis revealed activation of the Sonic hedgehog pathway in gastroblastoma and gene expression profiling showed that gastroblastomas grouped together and were most similar to Sonic hedgehog-type medulloblastomas. In summary, we have identified an oncogenic MALAT1-GLI1 fusion gene in all cases of gastroblastoma that may serve as a diagnostic biomarker. The fusion gene is predicted to encode a protein that includes the zinc finger domains of GLI1 and results in overexpression of GLI1 protein and activation of the Sonic hedgehog pathway.

The oncogenic transcription factor IRF4 is regulated by a novel CD30/NF-κB positive feedback loop in peripheral T-cell lymphoma.

Peripheral T-cell lymphomas (PTCLs) are generally aggressive non-Hodgkin lymphomas with poor overall survival rates following standard therapy. One-third of PTCLs express interferon regulatory factor-4 (IRF4), a tightly regulated transcription factor involved in lymphocyte growth and differentiation. IRF4 drives tumor growth in several lymphoid malignancies and has been proposed as a candidate therapeutic target. Because direct IRF4 inhibitors are not clinically available, we sought to characterize the mechanism by which IRF4 expression is regulated in PTCLs. We demonstrated that IRF4 is constitutively expressed in PTCL cells and drives Myc expression and proliferation. Using an inhibitor screen, we identified nuclear factor κB (NF-κB) as a candidate regulator of IRF4 expression and cell proliferation. We then demonstrated that the NF-κB subunits p52 and RelB were transcriptional activators of IRF4. Further analysis showed that activation of CD30 promotes p52 and RelB activity and subsequent IRF4 expression. Finally, we showed that IRF4 transcriptionally regulates CD30 expression. Taken together, these data demonstrate a novel positive feedback loop involving CD30, NF-κB, and IRF4; further evidence for this mechanism was demonstrated in human PTCL tissue samples. Accordingly, NF-κB inhibitors may represent a clinical means to disrupt this feedback loop in IRF4-positive PTCLs.

ALK-negative anaplastic large cell lymphoma is a genetically heterogeneous disease with widely disparate clinical outcomes.

Anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma (ALCL) is a CD30-positive T-cell non-Hodgkin lymphoma that morphologically resembles ALK-positive ALCL but lacks chromosomal rearrangements of the ALK gene. The genetic and clinical heterogeneity of ALK-negative ALCL has not been delineated. We performed immunohistochemistry and fluorescence in situ hybridization on 73 ALK-negative ALCLs and 32 ALK-positive ALCLs and evaluated the associations among pathology, genetics, and clinical outcome. Chromosomal rearrangements of DUSP22 and TP63 were identified in 30% and 8% of ALK-negative ALCLs, respectively. These rearrangements were mutually exclusive and were absent in ALK-positive ALCLs. Five-year overall survival rates were 85% for ALK-positive ALCLs, 90% for DUSP22-rearranged ALCLs, 17% for TP63-rearranged ALCLs, and 42% for cases lacking all 3 genetic markers (P < .0001). Hazard ratios for death in these 4 groups after adjusting for International Prognostic Index and age were 1.0 (reference group), 0.58, 8.63, and 4.16, respectively (P = 7.10 × 10(-5)). These results were similar when restricted to patients receiving anthracycline-based chemotherapy, as well as to patients not receiving stem cell transplantation. Thus, ALK-negative ALCL is a genetically heterogeneous disease with widely disparate outcomes following standard therapy. DUSP22 and TP63 rearrangements may serve as predictive biomarkers to help guide patient management.

Chromosomal rearrangements and copy number abnormalities of TP63 correlate with p63 protein expression in lung adenocarcinoma.

The TP63 gene encodes a member of the p53 family of transcription factors. Although TP53 is a well-known tumor suppressor gene, the role of p63 in tumorigenesis is controversial. Our group recently identified novel chromosomal rearrangements involving TP63 in approximately 6% of peripheral T-cell lymphomas, which correlated with a p63+/p40- immunohistochemical profile. As a subset of lung adenocarcinomas are p63+/p40-, we undertook the current study to examine the presence of TP63 rearrangements and correlate with p63/p40 expression. Next-generation sequencing was used to identify genomic rearrangements of TP63 in 37 adenocarcinomas. Confirmatory fluorescence in-situ hybridization (FISH) using a break-apart probe to the TP63 gene region and immunohistochemistry for p63 and p40 were performed on adenocarcinomas with TP63 rearrangements identified by mate-pair sequencing. Immunohistochemistry for p63 and p40 was performed on 45 additional adenocarcinomas, and FISH was performed on all adenocarcinomas with p63 positivity. TP63 rearrangement was identified in two adenocarcinoma specimens from a single patient. The rearrangement resulted in a complex rearrangement of 3q that fused B3GALNT1 at the 3' intron to TP63. FISH confirmed the rearrangement in both tumors. Immunohistochemistry staining for p63 was diffuse (>80% cells+) and p40 was negative. Of the 44 additional adenocarcinomas, 13 (30%) showed p63 expression; p40 was negative in all cases. No case showed rearrangement of TP63 by a break-apart FISH. However, extra copies of the intact TP63 locus were seen in the p63-positive areas of all 12 cases, with copy numbers ranging from three to seven. We have identified a novel chromosomal rearrangement involving TP63 in a p63+/p40- lung adenocarcinoma. Break-apart FISH testing can be used to diagnose this finding. Immunohistochemistry for p63 was not specific for this rearrangement, as nearly 33% of adenocarcinomas expressed p63. Additional copies of the intact TP63 locus were also a common finding and correlated with immunohistochemistry positivity for p63.

Prognostic irrelevance of ring sideroblast percentage in World Health Organization-defined myelodysplastic syndromes without excess blasts.

The presence of ≥ 15% bone marrow (BM) ring sideroblasts (RS) and < 5% blasts is required for a diagnosis of refractory anemia with ring sideroblasts. We examined the phenotypic and prognostic relevance of this "15%" RS threshold in 200 patients with myelodysplastic syndromes (MDS) without excess blasts and with ≥ 1% RS. The impact of RS% was assessed both as a continuous and categorical variable: < 5% (n = 56), 5%-14% (n = 32), 15%-50% (n = 79), and > 50% (n = 33). RS% correlated (P < .05) directly with age, platelet count, transfusion dependency, BM cellularity, and mutant SF3B1 and inversely with hemoglobin level, multilineage dysplasia, and high-risk karyotype; but did not correlate with IDH mutations. At a median follow-up of 33 months, 156 (73%) deaths and 24 (12%) leukemic transformations were documented. Neither univariate nor multivariable analysis showed significant effect for RS% on overall or leukemia-free survival, suggesting the limited prognostic value of quantifying BM RS in MDS.

SF3B1 mutations are prevalent in myelodysplastic syndromes with ring sideroblasts but do not hold independent prognostic value.

SF3B1 mutations were recently reported in myelodysplastic syndromes (MDSs), especially in the presence of ring sideroblasts (RSs). We sought to define the interaction between SF3B1 mutations, morphology, karyotype, and prognosis in MDS with more than or equal to 15% RS (MDS-RS). We studied 107 patients with MDS-RS, including 48 with refractory anemia with RS (RARS), 43 with refractory cytopenia with multilineage dysplasia (RCMD)-RS, 11 with refractory anemia with excess blasts-1 (RAEB1)-RS, and 5 with RAEB2-RS. SF3B1 mutations were detected in 53 (∼ 50%) patients: 35 RARS (73%), 16 RCMD-RS (37%), and 2 RAEB1-RS (18%). In univariate analysis, the presence of SF3B1 mutations was associated with better overall (P < .01) and leukemia-free (P < .01) survival; however, in both instances, significance was completely accounted for by World Health Organization morphologic risk categorization. In other words, when RARS and RCMD-RS were analyzed separately, there was no additional prognostic value from the presence or absence of SF3B1 mutations.

Trisomies in multiple myeloma: impact on survival in patients with high-risk cytogenetics.

Routine incorporation of FISH into multiple myeloma (MM) diagnostic testing has led to a better appreciation of the heterogeneity of genetic abnormalities associated with this disease. We studied a group of 484 patients with newly diagnosed symptomatic MM to better understand the prevalence of the various abnormalities and the prognostic significance of the overlapping abnormalities. A translocation involving the IgH locus and 1 of the 5 recurrent partner chromosomes was seen in 161 (33%) patients, and 275 (57%) had trisomy of at least 1 odd-numbered chromosome. High-risk FISH, defined as the presence of t(4;14), t(14;16), t(14;20), or loss of P53, was seen in 115 (24%) patients; the median overall survival for this group was 3.9 years, compared with "not reached" for standard-risk patients (P < .001). Among the patients with high-risk FISH, 49 patients who also had at least 1 trisomy had a median overall survival that was not reached, compared with 3 years for high-risk patients without a concurrent trisomy (P = .01). Based on the current findings, we conclude that the presence of trisomies in patients with t(4;14), t(14;16), t(14;20), or p53 deletion abnormalities in MM ameliorates the usual adverse impact associated with these prognostic markers.

Genome-wide analysis reveals recurrent structural abnormalities of TP63 and other p53-related genes in peripheral T-cell lymphomas.

Peripheral T-cell lymphomas (PTCLs) are aggressive malignancies of mature T lymphocytes with 5-year overall survival rates of only ∼ 35%. Improvement in outcomes has been stymied by poor understanding of the genetics and molecular pathogenesis of PTCL, with a resulting paucity of molecular targets for therapy. We developed bioinformatic tools to identify chromosomal rearrangements using genome-wide, next-generation sequencing analysis of mate-pair DNA libraries and applied these tools to 16 PTCL patient tissue samples and 6 PTCL cell lines. Thirteen recurrent abnormalities were identified, of which 5 involved p53-related genes (TP53, TP63, CDKN2A, WWOX, and ANKRD11). Among these abnormalities were novel TP63 rearrangements encoding fusion proteins homologous to ΔNp63, a dominant-negative p63 isoform that inhibits the p53 pathway. TP63 rearrangements were seen in 11 (5.8%) of 190 PTCLs and were associated with inferior overall survival; they also were detected in 2 (1.2%) of 164 diffuse large B-cell lymphomas. As TP53 mutations are rare in PTCL compared with other malignancies, our findings suggest that a constellation of alternate genetic abnormalities may contribute to disruption of p53-associated tumor suppressor function in PTCL.

Histiocytoid Sweet syndrome may indicate leukemia cutis: a novel application of fluorescence in situ hybridization.

BACKGROUND: In patients with malignancy-associated Sweet syndrome, a thorough evaluation for leukemia cutis should be considered. OBJECTIVE: We sought to describe the clinicopathologic characteristics of histiocytoid Sweet syndrome. METHODS: We retrospectively identified patients with histiocytoid Sweet syndrome at our institution from January 1992 through December 2010. We evaluated the underlying cutaneous infiltrate using immunohistochemistry and fluorescence in situ hybridization. RESULTS: We re-evaluated all 22 patients with hematologic malignancy-associated Sweet syndrome. Six patients had a monocytoid infiltrate that was consistent with histiocytoid Sweet syndrome; subsequent evaluation of these patients demonstrated cytogenetic abnormalities on prior bone-marrow biopsy specimens. Fluorescence in situ hybridization analysis was feasible in cutaneous specimens from 5 of the 6 patients and demonstrated the same cytogenetic abnormalities that were identified on prior bone-marrow biopsy specimens in 4 patients. Therefore, these 4 patients may have had a form of leukemia cutis. LIMITATIONS: This was a retrospective study. CONCLUSION: For patients with histiocytoid Sweet syndrome, an underlying hematologic malignancy, and a monocytoid infiltrate on biopsy specimen, fluorescence in situ hybridization of the cutaneous infiltrate may be beneficial to identify cytogenetic abnormalities that may indicate leukemia cutis.

Ancillary immunohistochemical and molecular testing in the classification of cutaneous sweat gland/duct neoplasms: A validation study with emphasis on histomorphologic correlation and pathological diagnosis.

Sweat gland neoplasms represent a challenging area of dermatopathology, as they are relatively uncommon and often histopathologically complex. Recent studies have uncovered distinct immunohistochemical and molecular profiles in several sweat gland neoplasms, including digital papillary adenocarcinoma (DPA), papillary eccrine adenoma/tubular apocrine adenoma (PEA/TAA), poroid family tumors (PFT)/porocarcinoma, and clear cell hidradenoma (CCH)/clear cell hidradenocarcinoma (CCHCa). To further evaluate the diagnostic utility of ancillary studies in various sweat gland neoplasms, we performed an independent validation study in a cohort of patients with acral and non-acral tumors (9 DPA, 8 PEA/TAA, 13 PFT, 5 porocarcinoma, 23 CCH, 7 CCHCa, 6 sweat gland carcinoma not otherwise specified). p63 immunohistochemistry (IHC) demonstrated a myoepithelial pattern in 8/8 DPA and 4 of 4 tested PEA/TAA cases, and showed a ductal pattern in all tested PFT/porocarcinoma and CCH/CCHCa cases (42/42). All PEA/TAA (8/8) cases were positive for BRAF V600E IHC. 5 of 12 tested PFT and 5/5 porocarcinoma cases showed either positive staining with NUT IHC or harbored YAP1::NUTM1 fusion gene by RNA sequencing. MAML2 fluorescence in situ hybridization (FISH) was positive in all CCH and CCHCa cases (23/23 and 7/7, respectively). Our results further support the usefulness of appropriate ancillary studies in precise classification of sweat gland tumors, which may be routinely applied in diagnostic pathology practice when morphologic evaluation is in doubt.

Differences in the distribution of cytogenetic subtypes between multiple myeloma patients with and without a family history of monoclonal gammopathy and multiple myeloma.

We previously reported an increased risk of monoclonal gammopathy of undetermined significance (MGUS) in first-degree relatives of MGUS and multiple myeloma patients. Here, we examine whether primary cytogenetic categories of myeloma differ between patients with and without a family history of MGUS or myeloma. We studied 201 myeloma patients with available data on family history and molecular cytogenetic classification. Myeloma with trisomies was more common in probands who had an affected first-degree relative with MGUS or myeloma compared with those without a family history (46.9% vs. 33.5%, P = 0.125); however, the difference was not statistically significant. Additional studies on the cytogenetic types of myeloma associated with familial tendency are needed.

Evaluation of revised IPSS cytogenetic risk stratification and prognostic impact of monosomal karyotype in 783 patients with primary myelodysplastic syndromes.

Cytogenetic classification by the revised international prognostic scoring system (IPSS-R) and the prognostic value of monosomal karyotype (MK) were assessed in 783 patients with primary myelodysplastic syndromes (MDS). At 22 months median follow-up, 562 (72%) deaths were recorded. Percentages of patients with IPSS-R "very good," "good," "intermediate," "poor," and "very poor" cytogenetic categories was 5, 63, 18, 4, and 10%, respectively. The corresponding median survivals were 21, 40, 24, 18, and 6.5 months and the inter-group differences (good vs. very good/intermediate/poor vs. very poor; P < 0.01) or similarities (very good vs. intermediate vs. poor; P = 0.79) were not significantly modified in multivariable analysis. Results were similar when analysis was restricted to 602 patients managed by supportive care. MK adversely affected survival in both poor and very poor karyotype groups (P < 0.01). In conclusion, we were unable to confirm the prognostic superiority of IPSS-R-very good karyotype or prognostically distinguish between very good, intermediate and poor karyotypes. Furthermore, we show additional prognostic information from MK in poor/very poor karyotype.

Spliceosome mutations involving SRSF2, SF3B1, and U2AF35 in chronic myelomonocytic leukemia: prevalence, clinical correlates, and prognostic relevance.

SRSF2, SF3B1, and U2AF35 (U2AF1) are the three most frequent genes involved with spliceosome mutations in myeloid malignancies. SF3B1 mutations are most frequent (~80%) in myelodysplastic syndromes (MDS) with ring sideroblasts (RS) but lack prognostic relevance. SRSF2 mutations are associated with shortened overall (OS) and leukemia-free survival (LFS) in both MDS and myelofibrosis. In this study of 226 patients with chronic myelomonocytic leukemia (CMML), mutational frequencies were 40% for SRSF2 (all affecting P95), 6% for SF3B1 (primarily K700E) and 9% for U2AF35 (mostly S34F and Q157P/R). These mutations were mutually exclusive and 54% of the patients displayed at least one mutation. The three mutation groups were phenotypically similar, with the exception of higher RS% (P < 0.0001) in patients with SF3B1 mutations. At a median follow-up of 15 months, 176 (78%) deaths and 32 (14%) leukemic transformations were documented. OS (median survivals of 17, 16, 17, and 20 months; P = 0.48) and LFS (leukemic transformation rates of 17, 13, 15, and 5%; P = 0.63) were similar among patients with none of the three mutations, SRSF2, SF3B1, or U2AF35 mutations, respectively. We conclude that SRSF2 is the most frequently mutated spliceosome gene in CMML but neither it nor SF3B1 or U2AF35 mutations are prognostically relevant.

Cutaneous extramedullary plasmacytoma: clinical, prognostic, and interphase cytogenetic analysis.

Extramedullary plasmacytoma (EMP) of the skin is a rare indolent neoplasm that shares morphological and immunophenotypic features with plasma cell myeloma (PCM), but the molecular features that distinguish these two entities have not been defined. We reviewed the clinical characteristics, course, and molecular abnormalities in 7 cases of cutaneous EMP (cEMP); 2 patients had primary cEMP and 5 had secondary cEMP. Two patients died of progressive extramedullary plasmacytoma, 1 without PCM; 1 patient who had only a hyperdiploid clone, died within 17 months of the diagnosis of cEMP; and 3 died of PCM. One patient, who had cEMP with a hyperdiploid clone and a 13q deletion, was alive 28 months after diagnosis. Our findings raise questions about the relative prognostic value of molecular aberrations observed in cEMP and PCM. The role of fluorescence in situ hybridization testing in predicting disease progression of cEMP remains to be defined.

Alternative lengthening of telomeres in primary hepatic neoplasms.

The alternative lengthening of telomeres (ALT) phenotype is characterized by ultra-bright telomeres on fluorescence in situ hybridization (FISH) and is a marker of a unique mechanism of telomere maintenance in tumors. ALT does not occur in normal tissues. ALT has been described in hepatocellular carcinoma (5-10%) and in primary hepatic angiosarcomas (75%). To study the frequency of ALT in other primary hepatic tumors, a wide range of primary hepatic neoplasms were retrieved. The tumors included the following: intrahepatic and hilar cholangiocarcinomas (N = 110), hepatic adenomas (N = 35), hepatocellular carcinomas (N = 30), fibrolamellar carcinomas (n = 11), combined cholangiocarcinoma-hepatocellular carcinomas (N = 8), carcinosarcoma (N = 10), hepatoblastomas (N = 5), hemangiomas (N = 4), angiosarcomas (N = 8), epithelioid hemangioendotheliomas (N = 10), calcified nested stromal epithelial tumor (N = 2), embryonal sarcoma (N = 2), rhabdoid tumor (N = 1), bile duct adenoma (N = 1), and angiomyolipoma (N = 1). For epithelial tumors, ALT-FISH was positive in one carcinosarcoma (10% of cases), one cholangiocarcinoma (1% of cases), and one combined hepatocellular carcinoma-cholangiocarcinoma (13% of cases). In the hepatocellular carcinoma component of both the carcinosarcoma and the combined hepatocellular carcinoma-cholangiocarcinoma, the tumor cells showed patchy marked nuclear pleomorphism akin to that described previously for chromophobe hepatocellular carcinoma, which are typically ALT FISH positive. The ALT-positive cholangiocarcinoma also showed patchy, striking nuclear pleomorphism. For soft tissue tumors, ALT was positive in two angiosarcomas (N = 2; 25% of cases). In summary, this study shows that ALT-FISH is positive in rare carcinosarcomas, cholangiocarcinomas, and combined cholangiocarcinoma-hepatocellular carcinoma. ALT is not a significant mechanism of telomere maintenance in hepatocellular adenomas or fibrolamellar carcinomas and was negative in all other tested primary hepatic neoplasms. ALT-FISH is also positive in a subset of primary hepatic angiosarcomas.

TP53 mutations and polymorphisms in primary myelofibrosis.

A total of 107 patients with chronic-phase primary myelofibrosis (PMF) were screened for TP53 mutations, which were detected in 4 (4%) cases: (i) E204E; GAG>GAA (silent exon 6); (ii) G245D; GGC>GAC (exon 7); (iii) R175H; CGC>CAC (exon 5); and (iv) six base insert (GGCGAG) after bp13767 (exon 6). Three (75%) of the four TP53-mutated cases also carried JAK2V617F whereas none were positive for MPL or IDH mutations. Two of the four TP53 mutated cases were also screened for TET2, ASXL1, DNMT3A, and EZH2 mutations and were negative. There was no significant difference in presenting features or survival between TP53 mutated and unmutated cases. TP53 exon 4 single nucleotide polymporphism (SNPs) data for codon 72 were available on 104 patients and included 56% with homozygous Arg72Arg, 33% with heterozygous Pro72Arg, and 11% with homozygous Pro72Pro. There were no significant differences among the three codon 72 genotypes in terms of presenting characteristics or survival.

Sole abnormalities of chromosome 7 in myeloid malignancies: spectrum, histopathologic correlates, and prognostic implications.

Among 6,565 consecutive abnormal cytogenetic reports at our institution, 3,192 (49%) constituted sole abnormalities, of which 230 (7%) involved chromosome 7: monosomy 7 (n = 98), 7q- (n = 51), der(1;7)(q10;p10) (n = 44), balanced translocations (n = 15), ring 7 (n = 13), and 7p- (n = 9). The most frequent histopathologic correlates were myelodysplastic syndromes (MDS; 28%), acute myeloid leukemia (AML; 17%), secondary or therapy-related MDS/AML (13%), primary myelofibrosis (PMF; 7%), and chronic myelomonocytic leukemia (6%). Monosomy 7 was the most frequent in each one of these disease categories except PMF where 7q- was more frequent. In primary MDS, patients with der(1;7)(q10;p10) (n = 13), compared to those with monosomy 7 (n = 30) or 7q- (n = 15), were less likely (P = 0.04) to display excess blasts or multilineage dysplasia but overall and leukemia-free survival adjusted for these variables revealed no significant difference between the three groups (P = 0.57 and 0.81, respectively). The current study does not prognostically distinguish monosomy 7 from 7q- or der(1;7), in MDS.