Although papillary thyroid carcinoma (PTC) displays strong heritability, no predisposing germ-line mutations have been found. We show that a common G/C polymorphism (rs2910164) within the ...pre-miR-146a sequence reduced the amount of pre- and mature miR-146a from the C allele 1.9- and 1.8-fold, respectively, compared with the G allele. This is matched by a similar decrease in the amount of each pre-miR generated from the corresponding pri-miR-146a in an in vitro processing reaction. The C allele also interfered with the binding of a nuclear factor to pre-miR-146a. The reduction in miR-146a led to less efficient inhibition of target genes involved in the Toll-like receptor and cytokine signaling pathway (TRAF6, IRAK1), and PTC1 (also known as CCDC6 or H4), a gene frequently rearranged with RET proto-oncogene in PTC. In an association study of 608 PTC patients and 901 controls, we found marked differences in genotype distribution of rs2910164 (P = 0.000002), the GC heterozygous state being associated with an increased risk of acquiring PTC (odds ratio = 1.62, P = 0.000007), and both homozygous states protective with odds ratio = 0.42 for the CC genotype (P = 0.003) and odds ratio = 0.69 for the GG genotype (P = 0.0006). Moreover, 4.7% of tumors had undergone somatic mutations of the SNP sequence. Thus, our data suggest that a common polymorphism in pre-miR-146a affects the miR expression, contributes to the genetic predisposition to PTC, and plays a role in the tumorigenesis through somatic mutation. Preliminary evidence suggests that these effects are mediated through target genes whose expression is affected by the SNP status.
Apart from alterations in the RET/PTC-RAS-BRAF pathway, comparatively little is known about the genetics of papillary thyroid carcinoma (PTC). We show that numerous microRNAs (miRNAs) are ...transcriptionally up-regulated in PTC tumors compared with unaffected thyroid tissue. A set of five miRNAs, including the three most up-regulated ones (miR-221, -222, and -146), distinguished unequivocally between PTC and normal thyroid. Additionally, miR-221 was up-regulated in unaffected thyroid tissue in several PTC patients, presumably an early event in carcinogenesis. Tumors in which the up-regulation (11- to 19-fold) of miR-221, -222, and -146 was strongest showed dramatic loss of KIT transcript and Kit protein. In 5 of 10 such cases, this down expression was associated with germline single-nucleotide changes in the two recognition sequences in KIT for these miRNAs. We conclude that up-regulation of several miRs and regulation of KIT are involved in PTC pathogenesis, and that sequence changes in genes targeted by miRNAs can contribute to their regulation.
Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is one of the two established Hodgkin lymphoma (HL) subtypes. The risk factors of NLPHL are largely unknown. In general, genetic factors are ...known to have a modest effect on the risk of HL; however, familial risk in NLPHL has not been previously examined. We conducted a population-based study by using the Finnish registries and evaluated the familial risk in NLPHL.
We launched a population-based search to identify patients with NLPHL and their relatives by examining the records of the Finnish Cancer Registry, established in 1953, and the official Finnish population registries. We collected a data set of 692 patients with NLPHL, identified their 4,280 first-degree relatives, and calculated the registry-based standardized incidence ratios (SIRs) for different cancers in the first-degree relatives. In addition, the primary tumor biopsies of HL-affected relatives were collected when possible, the HL diagnoses were re-reviewed by a hematopathologist, and the SIR for NLPHL was calculated on the basis of confirmed NLPHL diagnoses.
On the basis of confirmed NLPHL diagnoses, the SIR for NLPHL was 19 (95% CI, 8.8 to 36) in the first-degree relatives. The risk was most prominent in female relatives of young patients. The registry-based SIR for classical HL was 5.3 (95% CI, 3.0 to 8.8), and for non-Hodgkin lymphoma, it was 1.9 (95% CI, 1.3 to 2.6).
Our results implicate an unexpectedly high familial component in the development of NLPHL. Research is warranted to identify the putative genetic and environmental factors underlying this finding and to develop strategies for better management of patients with NLPHL and their relatives.
Mutated KIT and platelet-derived growth factor receptor alpha (PDGFRalpha) tyrosine kinases are the principal targets for imatinib mesylate in the treatment of gastrointestinal stromal tumors ...(GISTs). The frequency of activating KIT and PDGFRA gene mutations in most other histologic types of human cancer is not known.
KIT exons 9, 11, 13, and 17 and PDGFRA exons 11 and 17 of 334 human cancers were screened for mutations using sensitive denaturing high-performance liquid chromatography (DHPLC). In addition, all KIT exons from 9 to 21 of 115 tumors were screened. Thirty-two histologic tumor types were examined. Samples with abnormal findings in DHLPC were sequenced. Immunostaining for the KIT protein (CD117) was performed in 322 (96.4%) of the 334 cases.
Of the 3,039 exons screened, only 17 had mutation. All 17 cases with either mutated KIT (n = 15) or PDGFRA (n = 2) were histologically GIST tumors, whereas none of the other histologic types of cancer (n = 316) harbored KIT or PDGFRA mutation. KIT immunostaining was rarely positive except in GISTs (18 of 18), small-cell lung cancer (10 of 30; 33%), and testicular teratocarcinoma (four of 17; 24%). Wild-type KIT gene amplification or chromosome 4 aneuploidy was common (seven of 12) in non-GIST tumors with strong KIT protein expression when studied with fluorescence in situ hybridization.
Despite frequent KIT protein expression in some tumor types, KIT and PDGFRA gene mutations are uncommon in most human cancers. Cancer KIT expression is frequently associated with multiple copies of the wild-type KIT gene.
A strong clustering of Hodgkin lymphoma in certain families has been long acknowledged. However, the genetic factors in the background of familial Hodgkin lymphoma are largely unknown. We have ...studied a family of 4 cousins with a rare subtype of the disease, nodular lymphocyte predominant Hodgkin lymphoma. We applied exome sequencing together with genome-wide linkage analysis to this family and identified a truncating germline mutation in nuclear protein, ataxia-telangiectasia locus (NPAT) gene, which segregated in the family. We also studied a large number of samples from other patients with Hodgkin lymphoma, and a germline variation leading to the deletion of serine 724 was found in several cases suggesting an elevated risk for the disease (odds ratio = 4.11; P = .018). NPAT is thus far the first gene implicated in nodular lymphocyte predominant Hodgkin lymphoma predisposition.
Thyroid anaplastic (undifferentiated) carcinomas (TACs) comprise a morphologically heterogeneous group of tumors, which can arise in the background of differentiated papillary or follicular ...carcinoma. The thyroid epithelial differentiation varies in these tumors and has not been completely characterized. In this study, we immunohistochemically analyzed different variants TACs from 35 patients by using antibodies specific to 9 different keratin polypeptides, epithelial membrane antigen, thyroid transcription factor I (TTF-1), and thyroglobulin. These tumors were histologically divided into 3 categories: squamoid-cohesive (SC, 13 tumors), spindle cell sarcomatous (SS, 8 cases) and intermediate group, including tumors with giant cells and solid epithelioid components (GC, 18 tumors); 4 tumors had 2 components. The patients ages ranged from 40 to 89 years, with a mean age in all groups of 70 years. TTF-1 was present in only 2 of 9 of the SC tumors, and absent in all other TACs, but was present in entrapped differentiated components. Thyroglobulin was absent in all but 1 case. A complex keratin (K) pattern of stratified epithelia was typically seen in the SC tumors with extensive K7, K8, K17, K18, and K19, and variable K13 and K14 expression; EMA was also present. K16 was limited to squamous pearls in 1 tumor, and K10 was absent. The GC carcinomas typically had K8 and K18, whereas the expression of K7 was variable and that of K14, K17, and K19 sporadic; EMA was variably present in half of the cases. The keratins in spindle cell sarcomatous tumors were usually limited to K7, K8, and K18, often in limited numbers of cells. EMA was present in 1 case only. These results indicate a complex pattern of keratins in squamoid and giant cell TACs, similar to papillary carcinoma and suggesting the possibility of relationship. There was a progressive loss of epithelial differentiation and keratins in sarcomatoid TACs. Loss of TTF-1 is a nearly uniform feature of TAC and disallows the use of this marker to pinpoint a thyroid origin of these tumors. H
UM P
ATHOL 31:1139-1145.
Recent studies have suggested that lymphocyte-predominant Hodgkin's disease (LPHD) is both clinically and pathologically distinct from other forms of Hodgkin's disease, including classical Hodgkin's ...disease (CHD). However, large-scale clinical studies were lacking. This multicenter, retrospective study investigated the clinical characteristics and course of LPHD patients and lymphocyte-rich classical Hodgkin's disease (LRCHD) patients classified according to morphologic and immunophenotypic criteria.
Clinical data and biopsy material of all available cases initially submitted as LPHD were collected from 17 European and American centers, stained, and reclassified by expert pathologists.
The 426 assessable cases were reclassified as LPHD (51%), LRCHD (27%), CHD (5%), non-Hodgkin's lymphoma (3%), and reactive lesion (3%); 11% of cases were not assessable. Patients with LPHD and LRCHD were predominantly male, with early-stage disease and few risk factors. Patients with LRCHD were significantly older. Survival and failure-free survival rates with adequate therapy were similar for patients with LPHD and LRCHD, and were stage-dependent and not significantly better than stage-comparable results for CHD (German trial data). Twenty-seven percent of relapsing LPHD patients had multiple relapses, which is significantly more than the 5% of relapsing LRCHD patients who had multiple relapses. Lymphocyte-predominant Hodgkin's disease patients had significantly superior survival after relapse compared with LRCHD or CHD patients; however, this was partly due to the younger average age of LPHD patients.
The two subgroups of LPHD and LRCHD bore a close clinical resemblance that was distinct from CHD; the course was similar to that of comparable nodular sclerosis and mixed cellularity patients. Thorough staging is necessary to detect advanced disease in LPHD and LRCHD patients. The question of how to treat such patients, either by reducing treatment intensity or following a "watch and wait" approach, remains unanswered.
: Objectives
: Mantle cell lymphoma (MCL) is characterised by translocation t(11;14) (q13;q32) leading to rearrangement of bcl1/CCND1 and overexpression of the cell‐cycle regulatory protein cyclin ...D1. We assessed the significance of the cell proliferation rate as an outcome predictor with the five components of the International Prognostic Index (IPI) and the histological subtypes of MCL.
Patients and methods
: The hospital case records and histopathological material of 127 patients diagnosed with MCL in a single centre were reviewed. The cell proliferation rate was assessed by Ki‐67 immunostaining and mitosis counting. Cox's multivariate regression model was used in multivariate survival analyses. The median follow‐up time was 87 months.
Results
: The mantle zone/nodular subtype of the common variant (19%) was associated with median survival of 70 months, the diffuse subtype of the common variant (64%) of 35 months, and the blastoid subtype (17%) of 11 months (
P
< 0.001). Patients with Ki‐67 expression in ≥ 26% (the upper tertile) of the lymphoma cells had median survival of only 13 months as compared with 45 months in the rest of the patients (
P
< 0.001). In a multivariate analysis high Ki‐67 expression, Ann Arbor stage III–IV, and age over 60 yr had independent influence on survival, whereas serum lactate dehydrogenase level, the number of extranodal disease sites, and performance status did not.
Conclusions : The IPI may not be an optimal tool for outcome prediction in MCL, and a better prognostic index may be obtained by including Ki‐67 expression and possibly the histological subtype in the index.
The need for total thyroidectomy and extended for lymphadenectomy and the need for postoperative radioiodine ablation in the treatment of papillary thyroid carcinoma is continuously debated. Since ...less aggressive treatment in low-risk patients has been suggested, several scoring systems have been developed to identify low-risk patients. In the current study, we compared the AMES, MACIS and TNM staging systems in predicting carcinoma-specific mortality in papillary thyroid carcinoma. Between 1967 and 1994, 495 patients with papillary thyroid carcinoma were treated at the Department of Surgery, Helsinki University Central Hospital. Carcinoma-specific mortality in the AMES low-risk group, comprising 89.7% of these patients, was 2.4%. Corresponding figures for the MACIS were 89.9%, and 2.4%, and for the TNM 85.9% and 1.2%. The mortality ratio, at 10 years, between low-risk and high-risk patients was 22.2 for the AMES, 25.0 for the MACIS and 41.8 for the TNM system. The proportion of explained variance in the Cox model was 16.3 for the AMES, 30.0 for the MACIS taken as a conitinuous variable and 28.9 for the TNM stage. The TNM stage was on average superior to the MACIS or AMES score in predicting cancer-specific mortality of patients with papillary thyroid carcinoma. This may be explained by the fact that the TNM system includes the prognostic effect of nodal metastases, which is included in neither the MACIS nor AMES systems.
Clonal hematopoiesis driven by somatic heterozygous TET2 loss is linked to malignant degeneration via consequent aberrant DNA methylation, and possibly to cardiovascular disease via increased ...cytokine and chemokine expression as reported in mice. Here, we discover a germline TET2 mutation in a lymphoma family. We observe neither unusual predisposition to atherosclerosis nor abnormal pro-inflammatory cytokine or chemokine expression. The latter finding is confirmed in cells from three additional unrelated TET2 germline mutation carriers. The TET2 defect elevates blood DNA methylation levels, especially at active enhancers and cell-type specific regulatory regions with binding sequences of master transcription factors involved in hematopoiesis. The regions display reduced methylation relative to all open chromatin regions in four DNMT3A germline mutation carriers, potentially due to TET2-mediated oxidation. Our findings provide insight into the interplay between epigenetic modulators and transcription factor activity in hematological neoplasia, but do not confirm the putative role of TET2 in atherosclerosis.
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