Homozygosity for the WRN Helicase-Inactivating Variant, R834C, does not confer a Werner syndrome clinical phenotype.

Loss-of-function mutations in the WRN helicase gene cause Werner syndrome- a progeroid syndrome with an elevated risk of cancer and other age-associated diseases. Large numbers of single nucleotide polymorphisms have been identified in WRN. We report here the organismal, cellular, and molecular phenotypes of variant rs3087425 (c. 2500C > T) that results in an arginine to cysteine substitution at residue 834 (R834C) and up to 90% reduction of WRN helicase activity. This variant is present at a high (5%) frequency in Mexico, where we identified 153 heterozygous and three homozygous individuals among 3,130 genotyped subjects. Family studies of probands identified ten additional TT homozygotes. Biochemical analysis of WRN protein purified from TT lymphoblast cell lines confirmed that the R834C substitution strongly and selectively reduces WRN helicase, but not exonuclease activity. Replication track analyses showed reduced replication fork progression in some homozygous cells following DNA replication stress. Among the thirteen TT homozygotes, we identified a previously unreported and statistically significant gender bias in favor of males (p = 0.0016), but none of the clinical findings associated with Werner syndrome. Our results indicate that WRN helicase activity alone is not rate-limiting for the development of clinical WS.

A phase 2 trial of azacitidine and gemtuzumab ozogamicin therapy in older patients with acute myeloid leukemia.

This trial tested the safety and efficacy of a regimen consisting of hydroxyurea followed by azacitidine, 75 mg/m(2) for 7 days, and gemtuzumab ozogamicin, 3 mg/m(2) on day 8, in older patients with newly diagnosed acute myeloid leukemia. Those achieving a complete remission received 1 consolidation treatment followed by 4 cycles of azacitidine. The patients were stratified into good-risk (age 60-69 years or performance status 0-1) and poor-risk (age ≥70 years and performance status 2 or 3) groups. Specific efficacy and safety goals were defined as being supportive of further study of the regimen. Eighty-three patients were registered in the good-risk cohort and 59 in poor-risk cohort, with median age of 71 and 75 years, respectively. In the good-risk group, 35 patients (44%) achieved a complete remission. Median relapse-free and overall survivals were 8 and 11 months, respectively. Six patients (8%) died within 30 days of registration. In the poor-risk group, 19 (35%) achieved a complete remission. Median relapse-free and overall survivals were 7 and 11 months, respectively. Seven patients (14%) died early. The results of this trial met predefined goals for efficacy and safety for the poor-risk cohort but not the good-risk group. .

The accumulation of versican in the nodules of benign prostatic hyperplasia.

BACKGROUND: Proteoglycans, a complex group of extracellular matrix (ECM) molecules, are elevated in benign prostatic hyperplasia (BPH). Versican is a stromal proteoglycan present in prostate tissue. Versican expression is elevated in tissues with increased proliferation. Based on these observations, we determined the extent and distribution of versican expression in prostates with BPH. METHODS: The involvement of versican in BPH nodules was compared with levels in non-nodular transition (TZ) and peripheral zone (PZ) tissues from 18 human prostate glands using immunohistochemistry, Northern blots and/or QRTPCR to localize versican and quantify versican mRNA transcript levels, and Western blots to assess gene product levels. RESULTS: Increased versican immunoreactivity was observed in the stroma of BPH nodules. Higher steady state levels of versican variants V0, V1, and V3 mRNA transcript and gene product were detected in the nodular tissues than in the non-nodular TZ or PZ parenchyma. CONCLUSIONS: These results suggest that versican may play a role in nodule formation in BPH.

Mutation at the polymerase active site of mouse DNA polymerase delta increases genomic instability and accelerates tumorigenesis.

Mammalian DNA polymerase delta (Pol delta) is believed to replicate a large portion of the genome and to synthesize DNA in DNA repair and genetic recombination pathways. The effects of mutation in the polymerase domain of this essential enzyme are unknown. Here, we generated mice harboring an L604G or L604K substitution in highly conserved motif A in the polymerase active site of Pol delta. Homozygous Pold1(L604G/L604G) and Pold1(L604K/L604K) mice died in utero. However, heterozygous animals were viable and displayed no overall increase in disease incidence, indicative of efficient compensation for the defective mutant polymerase. The life spans of wild-type and heterozygous Pold1(+/L604G) mice did not differ, while that of Pold1(+/L604K) mice was reduced by 18%. Cultured embryonic fibroblasts from the heterozygous strains exhibited comparable increases in both spontaneous mutation rate and chromosome aberrations. We observed no significant increase in cancer incidence; however, Pold1(+/L604K) mice bearing histologically diagnosed tumors died at a younger median age than wild-type mice. Our results indicate that heterozygous mutation at L604 in the polymerase active site of DNA polymerase delta reduces life span, increases genomic instability, and accelerates tumorigenesis in an allele-specific manner, novel findings that have implications for human cancer.

Abnormal X: autosome ratio, but normal X chromosome inactivation in human triploid cultures.

BACKGROUND: X chromosome inactivation (XCI) is that aspect of mammalian dosage compensation that brings about equivalence of X-linked gene expression between females and males by inactivating one of the two X chromosomes (Xi) in normal female cells, leaving them with a single active X (Xa) as in male cells. In cells with more than two X's, but a diploid autosomal complement, all X's but one, Xa, are inactivated. This phenomenon is commonly thought to suggest 1) that normal development requires a ratio of one Xa per diploid autosomal set, and 2) that an early event in XCI is the marking of one X to be active, with remaining X's becoming inactivated by default. RESULTS: Triploids provide a test of these ideas because the ratio of one Xa per diploid autosomal set cannot be achieved, yet this abnormal ratio should not necessarily affect the one-Xa choice mechanism for XCI. Previous studies of XCI patterns in murine triploids support the single-Xa model, but human triploids mostly have two-Xa cells, whether they are XXX or XXY. The XCI patterns we observe in fibroblast cultures from different XXX human triploids suggest that the two-Xa pattern of XCI is selected for, and may have resulted from rare segregation errors or Xi reactivation. CONCLUSION: The initial X inactivation pattern in human triploids, therefore, is likely to resemble the pattern that predominates in murine triploids, i.e., a single Xa, with the remaining X's inactive. Furthermore, our studies of XIST RNA accumulation and promoter methylation suggest that the basic features of XCI are normal in triploids despite the abnormal X:autosome ratio.

Four-color flow cytometry shows strong concordance with bone marrow morphology and cytogenetics in the evaluation for myelodysplasia.

The ability of 4-color flow cytometry (FC) to help identify myelodysplastic syndromes (MDSs) was evaluated in 124 bone marrow aspirates from unselected patients with unexplained cytopenias and/or monocytosis. The morphologic features of bone marrow aspirate smears were correlated with FC and cytogenetic findings blindly, and patterns of antigen expression were compared with patterns seen in nonneoplastic and normal marrow specimens. Of 124 cases, 58 (46.7%) had definitive FC abnormalities ("flow-abnormal"), 19 cases (15.3%) had mild FC abnormalities of indeterminate significance, and 47 cases (37.9%) had essentially normal FC. Highly significant differences were identified between the flow-abnormal group and other groups in mean myeloid blast percentages and numbers of abnormal antigens expressed, even when the analysis was limited to cases with fewer than 5% myeloid blasts. Strikingly, flow-abnormal cases constituted 50 (89%) of the 56 morphologically abnormal cases and 31 (94%) of the 33 cytogenetically abnormal cases, demonstrating the strong concordance of FC-identified antigenic abnormalities with morphologic features and cytogenetics in the evaluation of patients with unexplained cytopenias.

So-called "inflammatory leiomyosarcoma'': a series of 3 cases providing additional insights into a rare entity.

Inflammatory leiomyosarcoma, a rare entity first described in 1995, has been characterized by smooth muscle differentiation, a near-haploid karyotype, and a surprisingly good prognosis. The morphology is similar to that of conventional leiomyosarcoma admixed with a chronic inflammatory infiltrate. Thus far, only 15 cases have been reported in the English language literature. We report the clinical and pathological features of 3 additional cases of inflammatory leiomyosarcoma. Two women (ages 64 and 25, respectively) and 1 man (age 32) presented with a thigh, ovary, and lung mass, respectively. Inflammatory symptoms, such as anorexia, fever, night sweats, abdominal pain, and diarrhea, coincided with the thigh and ovarian primaries. Immunohistochemical studies revealed diffuse positivity for desmin and poor expression for other smooth muscle and skeletal muscle markers (muscle-specific actin [0/3], alpha-smooth muscle actin 1/3 [focal], calponin [1/3], caldesmon [0/3], and myogenin [0/3]). CD68 was diffusely positive in both the histiocytes and spindle cell component in all cases. Ultrastructural evaluation of 1 case (lung primary) lacked definitive smooth muscle differentiation. Cytogenetic analysis in 1 of 2 cases that were karyotyped, identified a near-haploid karyotype, which has been reported in other cases of inflammatory leiomyosarcoma. The other case showed 2 clonal populations of cells with interstitial deletions of the short arm of chromosome 8 and the long arm of chromosome 9, respectively. The case without cytogenetic data was intimately associated with an ovarian mature teratoma. These data also suggest that inflammatory leiomyosarcoma may lack smooth muscle differentiation, characterized by diffuse immunoreactivity for desmin but lack of immunoreactivity for alpha-smooth muscle actin, calponin, and caldesmon. In addition, 2 of the 3 cases developed distant metastases to the lungs, which suggests that these lesions may have a worse prognosis than previously believed.

Deep-seated, well differentiated lipomatous tumors of the chest wall and extremities: the role of cytogenetics in classification and prognostication.

BACKGROUND: Intramuscular lipomas and atypical lipomatous tumors (ALT) are common deep-seated lipomatous tumors of the chest wall and extremities. Distinguishing between these two entities can be difficult based on histologic analysis alone. However, the cytogenetic profiles of ALT and intramuscular lipomas are distinct. Correct classification is important, because aggressive local disease recurrence occurs more frequently in patients with ALT than in patients with intramuscular lipoma. The authors examined their single institutional experience and correlated their classification with clinical features and outcome. METHODS: In the current study, 106 patients with deep-seated, well differentiated adipose tumors of the chest wall and extremities were classified as having ALT or intramuscular lipoma using a combined approach of histology and cytogenetics, if available. The classification was correlated with clinicopathologic features and follow-up data. RESULTS: Fifty-five patients were classified as having intramuscular lipoma and 51 were classified as having ALT. Classification did not correlate with age and gender (P = 0.28 and P = 0.96, respectively). Intramuscular lipomas were smaller than ALTs (P < 0.0001), but there was significant overlap between the 2 groups. ALT occurred preferentially in the lower extremity (P < 0.0009). Four percent of patients with intramuscular lipomas and 27% of patients with ALTs developed local disease recurrence (P = 0.0006). Disease recurrence did not correlate with patient age at diagnosis, patient gender, tumor size, and tumor location (P = 0.45, P = 0.26, P = 0.49, and P = 0.28, respectively). Within the subset of patients with ALTs, disease recurrence did not correlate with patient age at diagnosis, patient gender, or tumor location (P = 0.38, P = 0.54, and P = 0.86, respectively). CONCLUSIONS: Classification of deep-seated, well differentiated lipomatous tumors of the extremities and chest wall using a combined approach of histology and cytogenetics correlated well with biologic behavior/disease recurrence. This combined approach is advocated to better stratify patients for treatment purposes and follow-up.

Immortalization in a normal foreskin fibroblast culture following transduction of cyclin A2 or cdk1 genes in retroviral vectors.

Human diploid fibroblasts (HDF) rarely, if ever, undergo spontaneous transformation to an immortalized cell type. Here we report the immortalization of an HDF cell line following transduction with cyclin A2 or cdk1 human genes via retroviral vectors. Fluorescence in situ hybridization (FISH) studies using the retroviral vector as a probe indicate that these cell lines are monoclonal. No telomerase activity could be detected in these cell lines, and the telomere length in the immortalized cells was observed to be 10-20 kb longer than that in low-passage cells from the parental fibroblast line. Cytogenetic studies revealed that the immortal lines share common chromosomal aberrations. FISH studies with a probe for p53 revealed loss of one copy of this gene which was associated with reduced steady-state levels of both p53 and p53-regulated p21(WAF1/Sdi1/CIP1) messages in both quiescent and proliferating immortalized cultures relative to the parental cells. Additional FISH studies with probes for p16(INK4a) and Rb, carried out after the immortalized cells proliferated in excess of 100 population doublings, also revealed loss of one copy of these genes in both cell lines. These cell lines, together with the well-characterized parental cells, could provide useful research material for the study of the mechanisms of immortalization and of regulation of proliferative senescence in HDF.

Extended lifespan of Barrett's esophagus epithelium transduced with the human telomerase catalytic subunit: a useful in vitro model.

As there has been no previous information on the consequences of telomerase expression in genetically altered, mortal cells derived from pre-malignant tissue, we sought to determine the effect of hTERT (human catalytic subunit of telomerase reverse transcriptase) transduction of pre-malignant cell strains from Barrett's esophagus that do not contain telomerase activity and possess a finite lifespan. Primary cultures of Barrett's esophageal epithelium transduced with a retrovirus containing hTERT were characterized by growth factor requirements, cytogenetics and flow cytometry. Expression of telomerase lengthened telomeres and greatly extended the lifespan of hTERT transduced (hTERT+) Barrett's esophagus cells. Growth factor dependency of the hTERT+ cultures remained largely similar to the parental cultures, although there was a modest increase in the ability to grow in agar. Chromosomal instability, measured by both karyotypic and FISH (fluorescence in situ hybridization) analyses, was reduced but not abrogated by hTERT transduction, suggesting that telomerase expression can enhance genomic stability. However, the persistence of residual instability gave rise to new clonal and non-clonal genetic variants, and in one hTERT+ culture a new DNA aneuploid population was observed, the only time such a ploidy shift has been seen in Barrett's cell strains in vitro. These in vitro observations are analogous to the clinical progression to aneuploidy that often precedes cancer in Barrett's esophagus, and suggest that reactivation of telomerase may be permissive for continued genetic evolution to cancer. Long-lived Barrett's esophagus epithelial cultures should provide a useful in vitro model for studies of neoplastic evolution and chemopreventive therapies.

An unusual case of multiple giant myelolipomas: clinical and pathogenetic implications.

Myelolipomas are benign tumors composed of both mature adipose and myeloid tissues. They typically present as an incidental mass in one of the adrenal glands proper. However, they can occur in ectopic adrenal tissue or, rarely, without associated adrenal tissue in various locations and can grow to weights of several kilograms. These tumors have been linked to endocrinopathies, such as Cushing disease and congenital adrenal hyperplasia, which involve overproduction of adrenocorticotropic hormone. We report a case of three giant adrenal myelolipomas arising in a persistently virilized female with congenital adrenal hyperplasia, supporting a role for hormonal stimuli in myelolipoma formation.

Outcome after induction chemotherapy for older patients with acute myeloid leukemia is not improved with mitoxantrone and etoposide compared to cytarabine and daunorubicin: a Southwest Oncology Group study.

Complete remission and long-term survival rates are low for older adults treated for acute myeloid leukemia (AML). Because of favorable phase 2 data using mitoxantrone and etoposide, we conducted a phase 3 study (SWOG-9333) in which patients over 55 years of age with previously untreated AML were randomized to receive mitoxantrone (10 mg/m(2) per day x 5) and etoposide (100 mg/m(2) per day x 5) [ME], or cytarabine (200 mg/m(2) per day x 7) and daunorubicin (45 mg/m(2) per day x 3) [AD] as induction therapy. The randomization was stratified by age, onset of leukemia, and multidrug resistance phenotype. Over a 4-year period, 328 eligible patients from 66 institutions were enrolled. The complete remission rate was 34% (95% confidence interval [CI] 26%-41%) for patients in the ME and 43% (CI 35%-51%) for patients in the AD treatment arm (one-tailed P value.96). The rates of resistant disease were 43% (CI 35%-51%) and 34% (CI 27%-42%), respectively, for the 2 treatment arms (one-tailed P value.95). The estimated overall survival at 2 years was 11% (CI 6%-15%) and 19% (CI 12%-25%) for patients randomized to ME and to AD induction therapy, respectively (one-tailed P value.99). After accounting for the independent prognostic factors associated with survival (karyotype, performance status, age, white blood cell count), exploratory analysis suggested there was a worse survival for patients who received ME compared with AD induction therapy (2-tailed P value.0066). We conclude that the results of our study do not demonstrate any benefit to the use of ME induction chemotherapy instead of AD in older patients with AML.

Molecular targeting of platelet-derived growth factor B by imatinib mesylate in a patient with metastatic dermatofibrosarcoma protuberans.

PURPOSE: Dermatofibrosarcoma protuberans is caused by activation of the platelet-derived growth factor B (PDGFB) receptor, a transmembrane tyrosine kinase. We investigated the response of dermatofibrosarcoma protuberans to the tyrosine kinase inhibitor imatinib mesylate. PATIENTS AND METHODS: A patient with unresectable, metastatic dermatofibrosarcoma protuberans received imatinib mesylate (400 mg bid). Response to therapy was assessed by [18F]fluorodeoxyglucose (FDG) positron emission tomography, magnetic resonance imaging, and histopathologic and immunohistochemical evaluation. RESULTS: The patient was treated for 4 months with imatinib mesylate. The hypermetabolic uptake of FDG fell to background levels within 2 weeks of treatment, and the tumor volume shrank by over 75% during the 4 months of therapy, allowing for resection of the mass. There was no residual viable tumor in the resected specimen, indicating a complete histologic response to treatment with imatinib mesylate. CONCLUSION: Imatinib mesylate is highly active in dermatofibrosarcoma protuberans. The dramatic response seen in this patient demonstrates that inhibition of PDGFB receptor tyrosine kinase activity can significantly impact viability of at least one type of solid tumor.