A novel insulinoma tumor suppressor gene locus on chromosome 22q with potential prognostic implications.

The molecular mechanisms contributing to the tumorigenesis of insulinomas are still poorly understood. As moderate to high rates of LOH have been found on chromosome 22q in gastrinomas, we performed a finer deletion mapping study of chromosome 22q with 8 microsatellite markers in 15 insulinomas (4 malignant and 11 benign). Fourteen of 15 (93%) insulinomas revealed LOH on chromosome 22q, whereas the shortest region of overlap implicated a deletion of approximately 700 kb at 22q12.1-q12.2 with an LOH rate of up to 57% (8 of 14). Although the expressed sequence tag marker A006E25 that is localized in the hSNF5/INI1 gene on 22q11.2 revealed LOH in 50% of informative cases (7 of 14), no alterations in this gene could be identified by single strand conformational polymorphism analysis, direct DNA sequencing, or RNA expression analysis. Remarkably, the four malignant tumors showed a common deleted region between markers D22S345 and D22S1144 compared with none of the 11 benign insulinomas. The observed high frequency of chromosome 22q12 deletions in insulinomas is suggestive for a region compatible with harboring a tumor suppressor gene. The hSNF5/INI1 gene is most likely not the candidate gene, because no alterations could be identified. The distinct pattern of allelic loss identified in this chromosomal region appears to be an attractive candidate marker for further evaluation with regard to the discrimination between benign and malignant insulinomas.     

Chromosome 22q in pancreatic endocrine tumors: identification of a homozygous deletion and potential prognostic associations of allelic deletions

OBJECTIVE: A variety of human tumors frequently show allelic deletions of chromosome 22q, suggesting that inactivation of one or more tumor suppressor genes in this region is important for their tumorigenesis. METHODS: In this study, 23 patients with pancreatic endocrine tumors (PETs), including gastrinomas, VIPomas and non-functioning islet cell carcinomas, were analyzed for loss of heterozygosity (LOH) on chromosome 22q with 12 microsatellite and 7 sequence tagged site markers. RESULTS: LOH on chromosome 22q was identified in 22 of 23 (96%) PETs. Markers in the chromosomal region 22q12.1 revealed LOH rates up to 85%. Notably, one tumor revealed a homozygous deletion in a second region at 22q12.3. LOH at this locus occurred more frequently in tumors with distant metastases (10 of 11) compared with tumors without distant metastases (3 of 12; P=0.0057) and, overall, allelic loss of 22q is positively correlated with distant metastases (r=0.78; P<0.0001). CONCLUSIONS: These findings are suggestive for novel tumor suppressor gene loci at chromosome 22q that might contribute to the pathogenesis of PETs, especially to the development of distant metastases.     

Loss of heterozygosity and analysis of mutation of p53 in hepatocellular carcinoma

Abstract Thirty-six hepatocellular carcinoma (HCC) tissues obtained from 34 patients were classified according to histological diagnosis into six well-differentiated HCC, 20 moderately differentiated HCC and 10 poorly differentiated HCC. High molecular weight DNA was prepared from each tumour and the corresponding non-tumour tissue. Loss of heterozygosity (LOH) on chromosomes 4q, 5q, 10q, 11p, 16q, 17p, mutation of the p53 gene and polymorphism of intron 25 of the retinoblastoma (RB) gene were simultaneously analysed. The patients were composed of three cases of small HCC (the diameter of which was < 3 cm) and 31 cases of advanced HCC. Twenty-nine of 34 (85.3%) patients analysed had been exposed to hepatitis B virus and/or hepatitis C virus. The frequencies of LOH on seven chromosomes were 57.9% in 17p13.3, 45.1% in 17p, 45.1% in 11p, 41.9% in 5q, 41.9% in 16q24, 29.0% in 4q, 25.8% in 10q in advanced HCC (four of well differentiated, 18 of moderately differentiated and nine of poorly differentiated carcinoma). In contrast, LOH was observed on 4q, 5q, 16q and 17p in 33% (1/3) of the small HCC (two of well differentiated and one of moderately differentiated carcinoma). The mutation of the p53 genes and polymorphism of the RB gene were present in 25.8% (8/31) and 12.9% (4/31) of the advanced tumours, respectively, but the mutation was not found in small HCC. LOH on every chromosome and the p53 mutation were observed more frequently in more advanced tumours, and the genetic changes accumulated with the increase of the histopathological grade. These findings suggest that the accumulation of genetic changes in multiple tumour suppressor genes is involved in the progression of HCC.     

Association of poor prognosis with loss of 12q, 17p, and 18q, and concordant loss of 6q/17p and 12q/18q in human pancreatic ductal adenocarcinoma

OBJECTIVE: Pancreatic cancer is one of the diseases with the poorest prognosis, but the associated genetic alterations are not yet well understood. The genetic alterations reported to date in pancreatic cancer include frequent mutations of the KRAS, TP53, p16, and SMAD4 genes. Mutation of the TP53 gene was reported to be associated with a poor prognosis. In this study, we analyzed the association of loss of heterozygosity (LOH) with clinicopathological features to attempt to devise effective methods in the future for clinically applying our results to diagnosis and treatment. METHODS: A total of 55 tumors from patients with primary pancreatic ductal carcinomas (34 men and 21 women, mean average age 63.9 yr) in which all the relevant clinical and pathological data were available were analyzed. A total of 46 cases were surgically resected, and nine cases were not. Tumor cells as well as corresponding normal cells were collected by microdissection under a microscope, and DNAs were purified. Allelotype analysis was performed by the PCR-based method, and the results were statistically analyzed. RESULTS: LOH of > or =30% were observed on chromosome arms 17p (47%, 17/36), 9p (45%, 14/31), 18q (43%, 15/35), 12q (34%, 10/29), and 6q (30%, 10/33). LOH of 12q, 17p, and 18q were significantly associated with a poor prognosis. Concordant losses of 6q with 17p and 18q were significantly associated with a poor prognosis. Concordant losses of 6q with 17p and of 12q with 18q were also found. CONCLUSIONS: Because LOH of 12q, 17p, and 18q are significantly associated with a poor prognosis, mutation of the putative tumor suppressor genes on these chromosome arms may play significant roles in the disease progression. Concordant losses of 6q with 17p and of 12q with 18q suggest that protein products of putative tumor suppressor genes on 6q and 12q may function in association with TP53 and SMAD4, respectively.     

Allelic imbalance regions on chromosomes 8p, 17p and 19p related to metastasis of hepatocellular carcinoma: comparison between matched primary and metastatic lesions in 22 patients by genome-wide microsatellite analysis

To understand the molecular mechanisms of metastasis in hepatocellular carcinoma (HCC), it is necessary to identify the accumulating genetic alterations during its progression as well as those responsible for the acquisition of metastatic potential in cancer cells. In our previous study, using comparative genomic hybridization (CGH), we found that loss on chromosome 8p is more frequent in metastatic lesions than in matched primary tumors of HCC. Thus, 8p deletion might contribute to HCC metastasis. To narrow the location of metastasis-related alteration regions, we analyzed 22 primary and matched metastatic lesions of HCC by genome-wide microsatellite analysis. Common regions with high levels of allelic imbalance (AI) were identified on 17p, 8p11-cen, 8p21-23, 4q32-qter, 4q13-23, 16q, and 1p33. Regions with increased AI in metastatic lesions were 8p23.3, 8p11.2, 17p11.2-13.3, 4q21-22, 4q32-qter, 8q24.1, 9p11, 9q31, 11q23.1, 13q14.1-31, 13q32-qter, 16p13.3, 16q13, 16q22, and 19p13.1, and these were considered to be related to the metastasis phenotype. Among them, loss on 8p was again proved to be related to progression and metastasis of HCC, and 8p23.3 and 8p11.2 were two likely regions harboring metastasis-related genes. It was also shown for the first time in HCC that AI of 19p13.1 might also be related to metastatic potential. These results provide some candidate regions for further study to identify putative genes suppressing metastasis of HCC.     

Clinical and molecular analysis of combined hepatocellular-cholangiocarcinomas

BACKGROUND/AIMS: Combined hepatocellular-cholangiocarcinoma (HCC-CC) show dual hepatocellular and biliary epithelial differentiation. To better understand the relations between cholangiocarcinoma (CC), HCC-CC and hepatocellular carcinoma (HCC), we screened for genetic alterations. METHODS: A series of nine CC, 15 HCC-CC and three separated HCC and CC lesions ('collision tumors') were screened for loss of heterozygosity (LOH) using 400 microsatellite markers and for p53 and beta-catenin mutations. A comparison with a previously characterized series of 137 HCC was performed. RESULTS: In six cases of CC and HCC-CC, we identified TP53 gene mutations. A CTNNB1/beta-catenin was identified in two patients presenting collision tumors, but no mutations were found in CC or in HCC-CC. A high level of chromosome instability in both CC and HCC-CC was found. Recurrent specific LOH were identified at 3p and 14q in more than 50% of the CC and the HCC-CC cases, whereas these chromosomal regions were deleted in less than 10% of the HCC cases (P<10(-5)). Minimal common regions of deletion (MCRD) were defined at 3p24-p14 and 14q24-q32, respectively. CONCLUSIONS: These results suggest that combined HCC-CC are genetically closer to CC than HCC and common carcinogenesis pathways may be altered in HCC-CC and CC.     

Novel recurrent genetic imbalances in human hepatocellular carcinoma cell lines identified by comparative genomic hybridization

To search for recurrent and specific genomic alterations in human hepatocellular carcinoma (HCC), we examined 18 cell lines by comparative genomic hybridization (CGH), a molecular cytogenetic approach that allows positional identification of gains and losses of DNA sequences of the entire tumor genome. We report here a distinct pattern of multiple recurrent DNA copy-number gains and losses that include alterations frequently seen in other neoplasias as well as changes potentially specific for HCC. The most frequent gains were localized on 1p34.3-35, 1p33-34.1, 1q21-23, 1q31-32, 6p11-12, 7p21, 7q11.2, 8q24.1-24.2, 11q11-13, 12q11-13, 12q23, 17q11. 2-21, 17q23-24, and 20p11.1-q13.2. Recurrent losses were mapped on 3p12-14, 3q25, 4p12-14, 4q13-34, 5q21, 6q25-26, 8p11.2-23, 9p12-24, 11q23-24, 13q12-33, 14q12-13, 15q25-26, 18q11.2-22.2, and 21q21-22. Seventeen genomic imbalances are novel in HCC, thus extending significantly the map of genetic changes and providing a starting point for the isolation of new genes relevant in pathogenesis of liver neoplasia, as well as providing molecular probes for both diagnosis and monitoring treatment of the disease.     

Reciprocal relationship between methylation status and loss of heterozygosity at the p14(ARF) locus in Australian and South African hepatocellular carcinomas

Chromosome 9p21, a locus comprising the tumor suppressor genes (TSG) p16(INK4a) and p14(ARF), is a common region of loss of heterozygosity (LOH) in hepatocellular carcinoma (HCC). p14(ARF) shares exon 2 with p16 in a different reading frame. p14 binds to MDM2 resulting in a stabilization of functional p53. This study examined the roles of p14, p16 and p53 in hepatocarcinogenesis, in 37 Australian and 24 South African patients. LOH at 9p21 and 17p13.1, p14 and p16 mutation analysis, p14 and p16 promoter methylation and p14, p16 and p53 protein expression was examined. LOH at 9p21 was detected more frequently in South African HCC (P = 0.04). Comparable rates of p53 LOH were observed in Australian and South African HCC (10/22, 45%vs 13/22, 59%, respectively). Hypermethylation of the p14 promoter was more prevalent in Australian HCC than in South African HCC (17/37, 46%vs 7/24, 29%, respectively). In Australian HCC the prevalence of p14 methylation increased with age (P = 0.03). p16 promoter methylation was observed in 12/37 (32%) and 6/24 (25%) in Australian and South African HCC, respectively. Loss of p16 protein expression was detected in 14/36 Australian HCC whereas p53 protein expression was detected in 9/36. Significantly, a reciprocal relationship between 9p21 LOH and p14 promoter hypermethylation was observed (P < or = 0.05). No significant association between p14 and p53 was seen in this study. The reciprocal relationship identified indicates different pathways of tumorigenesis and likely reflects different etiologies of HCC in the two countries.     

17号染色体微卫星不稳定性和杂合性丢失与非小细胞肺癌的关系

目的　明确１７ 号染色体微卫星不稳定性（ＭＩ） 和杂合性丢失（ＬＯＨ） 与非小细胞肺癌（ＮＳＣＬＣ） 的关系。方法　对３５ 例ＮＳＣＬＣ肿瘤切除组织和肿瘤旁正常组织,采用聚合酶链反应微卫星长度多态性分析方法检测了１７ 号染色体上４ 个微卫星位点ＴＰ５３（１７ｐ１３－１）、ＴＨＲＡ１（１７ｑ１１－２１２）、Ｄ１７Ｓ５７９（１７ｑ１２２１）、Ｄ１７Ｓ８５５（１７ｑ２１） 的ＭＩ和ＬＯＨ。结果　３５ 例ＮＳＣＬＣ中,１７ 号染色体ＭＩ和（或）ＬＯＨ的发生率为６３％ （２４／３５）,其中ＭＩ为４０％ （１４／３５） ,ＬＯＨ 为３１％ （１１／３５）。同时表现有ＭＩ和ＬＯＨ 为９％ （３／３５） 。早期ＮＳＣＬＣ（ Ⅰ期和Ⅱ期） １７ 号染色体ＭＩ和（ 或）ＬＯＨ 发生率为７９％ （１５／１９）,明显大于晚期（ Ⅲ期）ＮＳＣＬＣ（４４％ ,７／１６,Ｐ＜０－０５） 。无纵隔淋巴结转移的ＮＳＣＬＣ的ＭＩ和（ 或）ＬＯＨ 发生率（８７％ ） 亦明显大于已有纵隔淋巴结转移者（４８％ ）,Ｐ＜ ０－０５。ＭＩ和（ 或）ＬＯＨ 在不同肿瘤组织类型以及不同组织细胞分化程度之间差异无显著性,Ｐ＞０．０５。结论　１７ 号染色体ＭＩ和ＬＯＨ 在ＮＳＣＬＣ的发生中可     

Neurofibromatosis type 1-related gastrointestinal stromal tumors: a special reference to loss of heterozygosity at 14q and 22q

Purpose  Multiple gastrointestinal stromal tumors (GISTs) rarely occur in patients with neurofibromatosis type 1 (NF-1). In contrast to sporadic GISTs characterized by frequent allelic losses of 1p, 14q and 22q and mutations of KIT or PDGFRA gene with the activation of the downstream RAS-MAPK pathway, the molecular pathogenetic mechanisms of NF-1-related GISTs (NF-1 GISTs) remain unclear. Methods  Thirty-one GISTs and two foci of Cajal cell hyperplasia (CCH) were obtained from five patients with NF-1. Phospho-MAPK p44/42 expression was examined by immunohistochemical stain. KIT and PDGFRA mutations were analyzed by PCR and direct sequencing methods. Loss of heterozygosity (LOH) was analyzed by PCR-based method with microsatellite markers on 14q and 22q. Results  Immunohistochemical expression of phospho-MAPK p44/42 was frequently found in NF-1 GISTs (23/25 cases, 92%). Neither the KIT nor PDGFRA mutation was detected in 25 NF-1 GISTs and 2 CCH. Among the informative cases, LOH was seen at 14q and 22q in 7/8 (87.5%) and 5/12 (41.7%) NF-1 GISTs, respectively. Such LOH was not detected in CCH, whereas it was detected in small GIST less than 1 cm in diameter. Conclusions  Our results support that KIT and PDGFRA mutations are very rare events in NF-1 GIST. Rather, activation of the Ras-MAPK pathway associated with the inactivation of the NF1 gene may play an important role in the cell proliferation of NF-1 GIST. Additionally, LOH at 14q and 22q may contribute to the relatively early phase of tumor development of NF-1 GIST.     

Deletion mapping of chromosome 4q22-35 and identification of four frequently deleted regions in head and neck cancers

Head and neck squamous cell carcinoma (HNSCC) is a diverse group of cancers that are frequently aggressive in their biologic behavior. Inactivation of tumor suppressor gene (TSG) is one of the most critical steps leading to HNSCC. Loss of heterozygosity analysis is very sensitive method for the detection of frequent allelic loss in a chromosomal locus. This method has been considered as an important evidence for the localization of TSGs. We analyzed loss of heterozygosity (LOH) at chromosome 4q22-35 region by using 14 polymorphic microsatellite markers in 83 matched normal and HNSCC tissues. LOH was detected at least in one location in 71 of 83 (86%) tumor tissues. Frequent deletions were detected at the location of microsatellite markers, D4S2909 (46%), D4S2623 (51%), D4S406 (48%), D4S1644 (45%) and D4S2979 (40%). Four different frequently deleted regions at 4q22, 4q25, 4q31 and 4q34-35 were observed. These regions include several putative TSGs such as Caspase-6, SMARCAD1, SMARCA5, SAP30 and ING2. Further molecular analysis of each gene should be performed to clarify their roles in head and neck squamous cell carcinogenesis.     

Association of 22q11 deletion with isolated congenital heart disease in three Chinese ethnic groups

BACKGROUND: Congenital heart disease (CHD) is the most common type of heart disease among children. About 75% of DiGeorge syndrome (DGS) and velo-cardio-facial syndrome (VCFS) includes CHD. A deletion within chromosome 22q11.2 has been identified in the majority of patients with DGS and VCFS. And 22q11.2 deletion has become one of the markers used to study CHD in these syndromes. Whether 22q11.2 deletion is associated with isolated CHD is not known and was the topic of this study. METHODS AND RESULTS: We studied the 22q11.2 deletion in three Chinese ethnic groups (Tai, Bai and Han people) with 19 sporadic, isolated CHD by genotype and haplotype analysis with D22S420 etc. 11 consecutive polymorphic microsatellite markers. Among 19 isolated CHD patients, four had Tetralogy of Fallot (TOF), five exhibited Ventricular Septal Defect (VSD), five showed Atrial Septal Defect (ASD) and 5 had Patent Ductus Arteriosus (PDA). In some isolated CHD patients, 3 Mb and 1.5 Mb deletion to chromosome 22q11.2 was found. 2 of 4 TOF (50%) and 1 of 5 VSD (20%) and 1 of 5 PDA (20%) respectively were found to have deletions at D22S944. CONCLUSIONS: 22q11.2 deletion can be detected in isolated TOF, VSD and PDA of three Chinese ethnic groups, without detectable 22q11.2 deletion in those isolated ASD patients examined thus far. Our finding may be the first to show the 22q11.2 deletion in sporadic, isolated PDA/VSD patients whose family members are without CHD. In addition, D22S420 etc. 11 consecutive polymorphic microsatellite markers are very useful for the determination of 22q11.2 deletion in isolated CHD in China.     

Discerning malignancy in adrenocortical tumors: are molecular markers useful?

OBJECTIVE: Adrenocortical carcinoma (ACC) is a rare neoplasm with poor prognosis. Discerning ACCs from benign adenomas histologically may be difficult if invasion into surrounding tissues or metastases are missing. DESIGN: In order to establish molecular markers for malignancy, we analyzed seven normal adrenals, three massive macronodular ACTH-independent adrenocortical hyperplasias (MMAHs), 30 adrenocortical adenomas (ACAs) and ten ACCs. METHODS: All tissues were studied for the presence of alterations in the p53 tumor suppressor gene using the PAb 1801 antibody, which detects mutant p53 protein and the pYNZ22 microsatellite marker to show loss of heterozygosity (LOH) at 17p, for expression of the proliferation-associated antigen Ki67 using the MIB1 antibody, for the rate of apoptotic tumor cells with the TdT-mediated dUTP biotin nick end labeling (TUNEL) method, and for LOH of 11q13 (menin gene locus) with the D11S956 microsatellite marker. RESULTS: 0/3 MMAH, 1/28 ACA and 3/10 ACC revealed immunopositive staining for p53. LOH for pYNZ22 was observed in 1/3 MMAH, 1/23 informative ACA and 6/6 informative ACC. The rate of apoptotic cells was significantly higher in ACC (P<0.0001 by ANOVA) than in ACA but there was some overlap between groups. The Ki67 index (% immunopositive cells) was 1.9+/-1.30% (mean+/-s.d.) in normal adrenals, 3.47+/-1.37% in MMAH, and 2.11+/-1.01% in ACA. ACC had the highest Ki67 index of 11.94+/-7.58% distinguishing all ACC from the ACA and MMAH studied with a cut-off level of 5%. LOH for 11q13 was detected in 2/3 MMAH, 5/26 ACA and 6/8 ACC. CONCLUSIONS: We conclude that a Ki67 index above 5% is a sensitive and specific indicator of ACC and may be useful in the differentiation of adenomas from carcinomas.     

Characterisation of dic(9;20)(p11-13;q11) in childhood B-cell precursor acute lymphoblastic leukaemia by tiling resolution array-based comparative genomic hybridisation reveals clustered breakpoints at 9p13.2 and 20q11.2

Although the dic(9;20)(p11-13;q11) is a recurrent chromosomal abnormality in paediatric B-cell precursor acute lymphoblastic leukaemia (BCP ALL), occurring in approximately 2% of the cases, its molecular genetic consequences have not been elucidated. In the present study, high-resolution genome-wide array-based comparative genomic hybridisation (array-CGH) and fluorescence in situ hybridisation (FISH) were used to characterise the 9p and 20q breakpoints (BPs) in seven childhood BCP ALLs with dic(9;20), which was shown to be unbalanced in all of them, resulting in loss of 9p13.2-pter. Five of the cases had loss of 20q11.2-qter, whereas two displayed gain of 20cen-pter. All BPs on 9p clustered in a 1.5 Mb segment of the sub-band 9p13.2; in three of the cases, the 20q BPs mapped to three adjacent clones covering a distance of 350 kb at 20q11.2. Thus, the aberration should be designated dic(9;20)(p13.2;q11.2). One of the ALLs, shown to have a complex dic(9;20), was further investigated by FISH, revealing a rearrangement of the haemapoietic cell kinase isoform p61 (HCK) gene at 20q11. The disruption of HCK may result in a fusion gene or in loss of function. Unfortunately, lack of material precluded further analyses of HCK. Thus, it remains to be elucidated whether dic(9;20)(p13.2;q11.2) leads to a chimaeric gene or whether the functionally important outcome is loss of 9p and 20q material.     

Complex congenital heart disease in unaffected relatives of adults with 22q11.2 deletion syndrome

The 22.q11.2 deletion syndrome (22q11DS) is a common genetic condition associated with 22q11.2 microdeletions and classically has included congenital heart disease (CHD) as a part of the variable expression. Some evidence has shown that relatives of those with 22q11DS might be at an increased risk of CHD in the absence of 22q11.2 deletions. We obtained a detailed family history of CHD in the first- to third-degree relatives (n = 2,639) of 104 adult probands with 22q11DS. We compared the prevalence of CHD in the relatives without 22q11.2 deletions to the published general population prevalence. We also investigated the effect of CHD in the probands on prevalence of CHD in the relatives. Of the 104 probands with 22q11DS, 14 (13.5%) had 17 relatives (17 of 2,639, 0.6%) with CHD. Of 66 probands with CHD, 15 (0.9%) of their 1,663 relatives had CHD, a significantly greater prevalence than that for the relatives of probands without CHD (0.2%, 2 of 976, p = 0.041, odds ratio 4.43, 95% confidence interval 1.03 to 40.00). In relatives of probands with CHD, the prevalence of those with severe CHD (0.36%) was significantly elevated compared to population expectations (0.061%, p = 0.007, odds ratio 5.88, 95% confidence interval 2.16 to 12.85). In conclusion, these results support a heritable susceptibility to CHD in families of probands with 22q11DS, in addition to that imparted by microdeletion 22q11.2. The occurrence of CHD in relatives might be related to the expression of CHD in the proband with 22q11DS. These findings have potential implications for the genetic counseling of families of those with 22q11DS and support the notion that interacting genetic variants might contribute to the variable expression of 22q11DS.     

Allelotyping of follicular thyroid carcinoma: frequent allelic losses in chromosome arms 7q, 11p, and 22q

The genetic mechanisms involved in development of follicular thyroid carcinoma are poorly understood, although allelic losses (LOH) in this type of tumor have been reported in small panels of follicular thyroid carcinomas examined in earlier studies. To clarify the real frequency of allelic loss we carried out a genome-wide allelotyping study of 66 follicular thyroid carcinomas using 39 microsatellite markers representing all nonacrocentric autosomal arms. The mean frequency of LOH was 9.2%, and the mean fractional allelic loss was 0.09. The most frequent allelic losses were detected in 7q (28%), 11p (28%), and 22q (41%). When we compared these results with our previous allelotyping studies using identical markers in other types of thyroid cancers, the 9.2% mean frequency of allelic loss detected in follicular thyroid carcinomas was higher than that in papillary thyroid carcinomas (3%), but not as high as that detected in anaplastic thyroid carcinomas (20%). Frequent allelic losses of markers on chromosomes 7q, 11p, and 22q suggest locations to examine for the presence of suppressor genes associated with the development of follicular thyroid carcinoma.     

Totipotent stem cells bearing del(20q) maintain multipotential differentiation in Shwachman Diamond syndrome

SBDS /7q11 gene mutations underlie the congenital Shwachman Diamond syndrome (SDS), characterized by bone marrow failure and high risk of haematological malignancies. In two cases of SDS with bone marrow failure and isolated del(20q) interphase fluorescence in situ hybridization (I-FISH) found no abnormalities in FHIT /3p14.2, IKZF1 /7p13, D7S486/7q31, PTEN /10q23.3, WT1 /11p13, ATM /11q23, D13S25/13q14, TP53 /17p13, NF1 /17q11, SMAD2 /18q21, RUNX1 /21q22. Fluorescence immunophenotype combined with I-FISH found del(20q) in a totipotent haematopoietic stem cell (CD34⁺, CD133⁺) and downstream myelocyte (CD33⁺, CD14⁺, CD13⁺), erythrocyte (Glycophorin A⁺) and lymphocyte lineages (CD19⁺, CD20⁺, CD3⁺, CD7⁺). These findings and clinical follow-ups confirm the benign course of SDS with isolated del(20q).     

Expression of cyclin D1, cyclin E, cdk4 and loss of heterozygosity of 8p, 13q, 17p in hepatocellular carcinoma: comparison study of childhood and adult hepatocellular carcinoma

AIMS/BACKGROUND: In hepatitis B virus-related hepatocellular carcinoma (HCC), at least 20-40 years of continuous necro-inflammation is necessary for the hepato-carcinogenesis to occur. However, HCC in childhood shows an unusually short latent period and rapid progression. In our previous report, mutation of c-met was found only in childhood HCC, but not in adult HCC. In order to determine the specific biological tumorous features of childhood HCC, a comparison study of childhood and adult HCC was performed. METHODS: Eighteen cases of HBV positive HCC (nine children and nine adults aged more than 40 years) were selected. The expression of G1 phase regulatory proteins (cyclin D1, cyclin E and cdk4) was studied using immunohistochemical methods. Loss of heterozygosity (LOH) on chromosomal arms 8p, 13q and 17p was analyzed. RESULTS: Cyclin D1 expression was significantly lower in childhood HCC than in adult HCC (cases of cyclin D1 expression under 3+: childhood 5/9 vs. adult 1/9, p=0.046). No difference in cyclin E and cdk4 expression was found between childhood and adult HCC. LOH frequency on 13q was relatively higher in childhood than in adult HCC (66.7% vs. 22.2%, p=0.058). LOH frequency on 8p and 17p was 44.4% and 33.3% in childhood HCC and 44.4% and 75% in adult HCC with no statistical significance between the two groups. CONCLUSION: Our data suggest that childhood HCC may be less dependent on cyclin D1 protein for tumor growth and progression than adult HCC, and that the LOH on 13q may be an important feature of childhood HCC.