Allelic losses on chromosome arm 10q and mutation of the PTEN (MMAC1) tumour suppressor gene in primary and metastatic malignant melanomas

Malignant melanomas frequently show loss of alleles on the long arm of chromosome 10. The PTEN (MMAC1) gene has been identified as a tumour suppressor gene at 10q23.3 that is mutated in various types of advanced human cancers. We have investigated a series of 40 sporadic melanomas from 37 patients (15 primary cutaneous melanomas and 25 melanoma metastases) for allelic losses on chromosome 10, as well as for deletion and mutation of the PTEN gene. Microsatellite analysis revealed loss of heterozygosity at loci located on 10q in tumours from 15 of 34 patients investigated (44%). Somatic PTEN mutations were identified in melanomas from 4 of 37 patients (11%), all of whom had metastatic disease. In two of these patients, the tumours had additionally lost one PTEN allele, indicating complete loss of wild-type PTEN in the tumour cells. Our findings corroborate that loss of heterozygosity on chromosome 10 is a frequent aberration in malignant melanomas and implicate PTEN as a tumour suppressor gene inactivated by somatic mutation in a fraction of these tumours. Received: 1 September 1999 / Accepted: 22 December 1999     

肝细胞癌8号染色体微卫星变异及其与临床病理特征的关系

目的　探讨肝细胞癌 (HCC)微卫星变异的特点及其与临床病理表现的相关性。方法采用毛细管电泳DNA分析系统 ,对 5 6例HCC中 8号染色体上 10个微卫星的杂合子丢失 (LOH)、微卫星不稳定性 (MSI)和等位基因失衡 (AI) 3种变异特征进行检测。结果　 5 6例HCC在 8号染色体上 10个基因位点发生LOH的总频率为 6 6 1% (37/ 5 6 ) ,LOH以D8S2 6 1最高为 5 3 5 % (2 3/ 4 3) ,其次为D8S172 1(5 2 5 % )和D8S1771(5 2 5 % )。D8S2 77基因位点 ,血清HBsAg阳性患者的LOH频率显著高于HBsAg阴性者 (P <0 0 1) ,D8S2 6 1、D8S2 98和D8S1733基因位点 ,血清HBsAg阴性患者的LOH频率显著高于HBsAg阳性者 (P <0 0 1) ;D8S2 98和D8S1771基因位点 ,直径 >3cm肿瘤的LOH率明显高于≤ 3cm组 (P <0 0 5和P <0 0 1) ;在D8S172 1基因位点 ,无包膜或包膜不完整的肿瘤的LOH显著高于包膜完整的肿瘤 (P <0 0 1) ;D8S2 98和D8S1771基因位点 ,肝内转移者的LOH明显高于无肝内转移者 (P <0 0 5 )。MSI的频率为 12 5 % (7/ 5 6 ) ,AI的频率为 19 6 % (11/ 5 6 )。结论HCC在 8号染色体上存在广泛的微卫星变异 ,其中LOH方式在HCC的发生和发展过程中起重要作用 ,MSI的作用次之。特定基因位点的LOH与临床和病理学参数有一定的相关性     

Genetic alterations and protein expression of HER2 and chromosome 17 polysomy in breast cancer

HER2/neu alteration detection in breast cancer is important for decision making of the HER2-targeted therapy. We retrospectively analyzed the HER2/neu status by fluorescence in situ hybridization and HER2 protein expression by immunohistochemistry in a cohort of 481 patients with invasive breast cancer. Fluorescence in situ hybridization showed that 57.4% of cases exhibited HER2 amplification but 41.4% did not, and 1.2% exhibited an equivocal status. Immunohistochemistry showed that 10.4%, 16.8%, 38.3%, and 34.5% of cases had scores of 0, 1+, 2+, and 3+, respectively. The HER2 status showed a moderate agreement with HER2 expression with a score of 0, 1+, and 3+ (κ = 0.576, P < .05), and the concordance rate was 90%, 61.7%, and 83.1%, respectively. The HER2 amplification occurred more likely in cases with higher immunohistochemistry scores (P < .001), and polysomy 17 was observed in 28.3% of cases, but more frequently in the HER2 amplification subgroup (33.3%) than in the HER2 nonamplification subgroup (20.1%) (P < .05). There was no significant correlation between the frequency of polysomy 17 and immunohistochemistry scores (P > .05). In the immunohistochemistry 2+ group, 56.5% cases showed HER2/neu amplification, and polysomy 17 occurred more likely in the HER2 amplification subgroup (34.6%) than in the HER2 nonamplification group (13.0%) (P < .001). We concluded that the HER2 status was correlated with HER2 protein expression levels, and it is necessary to determine the HER2 status for cases with immunohistochemistry 2+. The frequency of polysomy 17 was correlated with the HER2 copy number and partially contributed to HER2/neu amplification but not HER2 protein expression.     

20q13.2 Amplification in intraductal hyperplasia adjacent to in situ and invasive ductal carcinoma of the breast

The 20q13 region harboring recently described putative oncogenes is frequently amplified in invasive ductal carcinoma (IDC). The aim of this study was to examine the 20q13 copy number in intraduct hyperplasia (IH), atypical duct hyperplasia (ADH), and ductal carcinoma in situ (DCIS) adjacent to IDC. In 5 patients, comparative genomic hybridization (CGH) after laser microdissection revealed 20q13 amplification in four of five cases of IH, in all of three cases of IH with atypia, all five of DCIS, and all five of IDC. Fluorescence in situ hybridization (FISH) confirmed the amplification at 20q13.2 in IH in the two specimens analyzed. The amplification rate, however, was higher in DCIS and IDC. In phenotypically normal ductal epithelium normal values were found for 20q13 copy number by FISH (n=2) and CGH (n=5). Although the number of cases presented here is small, our results suggest that mutations in the 20q13.2 region in IH may be associated with accelerated proliferation and hyperplasia of the ductal epithelium. Progression to DCIS and ICD is accompanied by a further increase in the 20q13.2 copy number. Received: 17 March 1999 / Accepted: 22 June 1999     

Impact of chromosome 17 centromere region assessment on HER2 status reported in breast cancer

Recent studies have indicated that polysomy 17 is a rare event in breast cancer, and polysomy is usually mimicked in FISH analysis by gain or amplification of the centromere covered by the chromosome 17 centromere probe. To estimate the impact of chromosome 17 centromere assessment on routine practice, we conducted a retrospective re-classification study.Four hundred and five consecutive cases were selected. The original molecular pathology reports were available. Centromere 17 copy counts were ignored in the reassessment.Altogether, nineteen (4.69%) discrepant cases were found, from which five (1.23%) were considered originally non-amplified but had an HER2 copy number >6. Therefore, we reclassified them as HER2-amplified, while fourteen (3.46%) cases were originally considered amplified with 6 or fewer HER2 signals/cell.The discrepant cases found in our reassessment study would require further high-resolution genetic analysis to resolve the disagreement. On the other hand, our result also highlights that for the vast majority of breast cancer cases traditional FISH examination is still adequate to reach the correct diagnosis. This diagnostic gap must be filled by more sophisticated genetic examinations. Moreover, upcoming HER2 guidelines should consider the aid that high-resolution karyotyping can give to the diagnostic algorithm.     

Chromosome 3p and breast cancer

 Solid tumors in humans are now believed to develop through a multistep process that activates oncogenes and inactivates tumor suppressor genes. Loss of heterozygosity at chromosomes 3p25, 3p22–24, 3p21.3, 3p21.2–21.3, 3p14.2, 3p14.3, and 3p12 has been reported in breast cancers. Retinoid acid receptor β2 (3p24), thyroid hormone receptor β1 (3p24.3), Ras association domain family 1A (3p21.3), and the fragile histidine triad gene (3p14.2) have been considered as tumor suppressor genes (TSGs) for breast cancers. Epigenetic change may play an important role for the inactivation of these TSGs. Screens for promoter hypermethylation may be able to identify other TSGs in chromosome 3p. Alternatively, use of an “epigenetic modifier” may enhance the response to another type of agent for breast cancer. Received: April 30, 2002 / Accepted: May 27, 2002     

Adenoid cystic carcinoma arising in an adenomyoepithelioma of the breast

 Adenomyoepithelioma is a mixed epithelial and myoepithelial tumour. In rare cases adenomyoepitheliomas give rise to carcinomas with epithelial, myoepithelial, or mixed epithelial and myoepithelial differentiation. Carcinomas arising in adenomyoepithelioma range from low grade to high grade, and 15 cases have been reported in the literature. We describe a 36-year-old woman with a very rare adenoid cystic carcinoma arising in a tubular adenomyoepithelioma. The histogenesis of carcinoma arising in an adenomyoepithelioma is discussed. Received: 15 September 1997 / Accepted: 10 October 1997     

Three discrete areas within the chromosomal 8p21.3-23 region are associated with the development of breast carcinoma of Indian patients

Deletion in the 22.9 -Mb chromosomal (chr.) 8p21.3-23 region has been shown to be necessary for the development of breast carcinoma (CaBr). In this study, we have attempted to detect the minimal deleted region(s) in the chr.8p21.3-23 region in 62 primary breast lesions having 56 CaBr tumors and six other breast lesions of Indian patients using 15 microsatellite markers. The loss of heterozygosity (LOH) was observed for at least one marker in 96.4% (54/56) of the CaBr samples. Three discrete minimal deleted regions with high frequencies of LOH (39-65%) were identified in the chromosomal 8p23.1-23.2 (D1), 8p23.1 (D2) and 8p 21.3-22 (D3) regions within 2.03, 0.41, 2.47 Mb, respectively. No significant correlation was observed with the high deleted regions and the different clinicopathological parameters. Interestingly, 51.8% (29/56) CaBr samples showed either loss of chr.8p or interstitial deletions in this arm, indicating the importance of chr.8p in the development of CaBr. The pattern of allelic loss in the bilateral lesions had indicated that the lesions were clonal in origin and probably the deletion in the D3 region was the early event among the D1-D3 regions. Thus, our data have indicated that the D1-D3 regions could harbor candidate tumor suppressor gene(s) (TSGs) associated with the development of CaBr.     

人宫颈癌组织染色体部分位点杂合性丢失

了解人宫颈癌组织中3，6，11和18号染色体部分位点杂合性丢失的分布状况，为宫颈部相关基因的定位以及临床诊断分子标志的筛选提供依据。采用宫颈癌基因组中3，6，11和18号染色体上的8个微卫星标志，对源自宫颈癌等高发区的宫颈癌活检标本，以PCR－变性电泳－银染的方法检测上述位点的杂合性丢失。其中在染色体3p14,18q21等位点存在较高频率的杂合性丢失。结果表明杂合性丢失是宫颈癌癌变过程中常见的遗传性改变，宫颈癌中存在杂合性丢失的高频区，提示相应位点存在潜在的抑癌基因。     

Amplification units and translocation at chromosome 17q and c-erbB-2 overexpression in the pathogenesis of breast cancer

 Hyperplasia without and with atypia is considered to be a precursor lesion for certain breast carcinomas. The cytogenetic events and the molecular pathology involved in the multistep process from normal to invasive carcinoma are unknown. To characterise the sequence of early genetic abnormalities of chromosome 17q and their biological consequences in the pathogenesis of breast cancer, we performed immunohistochemistry on 451 breast tissues including 180 normal breast specimens, 28 hyperplastic lesions without atypia and 44 with atypia, 100 cases of ductal carcinoma in situ (DCIS) and 99 cases of invasive ductal carcinoma. We correlated the overexpression of the c-ErbB-2 protein, the histological and the recently proposed differentiation classification of DCIS with the extent of DCIS. For fluorescence in situ hybridisation (FISH) analysis, different probes spanning the 17q region including the c-erbB-2 gene locus and those which are found adjacent, were used. Reverse painting and comparative genomic hybridisation (CGH) were performed on several breast cancer cell lines. c-ErbB-2 overexpression was observed in only 29% of DCIS and 23% of invasive carcinomas, but not in hyperplastic and normal tissue. c-ErbB-2 overexpression is correlated with poor differentiation in DCIS but not in invasive carcinoma. In DCIS, there was no correlation with the histological subtype classification. The average extent of DCIS is significantly increased from 13.81 mm in c-ErbB-2 negative cases to 29.37 mm in c-ErbB-2 positive cases. The increase was considered to be a possible consequence of the overexpression and is probably due to the previously described motility enhancing effect of the c-ErbB-2 protein. The histological and differentiation classification of DCIS did not correlate with the extent of disease. Using FISH, amplified genes at 17q12, always including the c-erbB-2 gene, were detected in all cases of DCIS and invasive carcinoma with c-ErbB-2 overexpression. The centromeric region and the NF1 locus, which is located between the centromere and c-erbB-2, were not amplified in any of the DCIS and invasive breast carcinomas, but co-amplification of the myeloperoxidase gene was detected in 3/5 DCIS and 1/5 invasive carcinomas with c-ErbB-2 overexpression. In contrast to c-erbB-2, immunohistochemical overexpression of their respective gene products was not observed. FISH, reverse painting and CGH show similar amplified genes with amplified c-erbB-2 in c-ErbB-2 overexpressing SK-BR-3 and BT474 human breast cancer cells. The amplified genes are part of two different amplicons. Extensive modifications of the 17q chromosomal region, caused by translocation, were also observed in these cell lines. It is concluded that the modifications of chromosome 17q, inducing overexpression of c-ErbB-2 protein, occur at the level of transition from hyperplasia to DCIS. They are preserved in invasive carcinoma with overexpression of c-ErbB-2 protein. This had led to the hypothesis that these modifications at 17q may lead to a larger extent of DCIS. Received: 23 July 1996 / Accepted: 9 December 1996     

Molecular study of clonality in multifocal and bilateral breast tumors

The clonal origin of multiple tumors in the same individual has long been debated. The main aim of this study is to find out whether multiple tumors in same individuals originated from a single clone. In our previous work (Pathol. Res. Pract. 199 (2003) 313-321), the deletion at chromosome1p36 was found to occur early because of common allelic loss in the bilateral tumors. In order to further investigate the findings about the clonality of tumors, eight tumors from four patients (two synchronous bilateral breast carcinoma [biBC], one case with breast carcinoma in one breast and multiple calcified fibroadenoma nodules in another breast, and one case with multifocal fibroadenosis in one breast) were subjected to polymerase chain reaction (PCR) to detect (a) loss of heterozygosity (LOH) and microsatellite size alterations (MA) using microsatellite markers distributed over five chromosomal arms 11p/q, 13q and 17p/q, and (b) Cyclin D1 amplification. Some markers were intragenic for BRCA1, BRCA2, BRCAX, ATM, TP53, and RB1. Although a few cases were studied, our findings suggest that in at least a proportion of patients multiple tumors may arise from a single clone.     

Adenomyoepithelioma of the breast with malignant features

 The clinico-pathological features of 7 cases of adenomyoepithelioma of the breast with features suggestive of malignancy are presented. There was a high incidence of local tumour recurrence, in 2 cases as high-grade infiltrating carcinoma of the breast of no special type (”ductal”, grade III). One patient died as the result of a clinically diagnosed cerebral metastasis. Histological examination of the primary breast tumours reveals two main patterns: (1) tumours consisting in part of typical adenomyoepitheliomas but which merge with areas of obviously invasive malignant cells and (2) neoplasms that have the overall architecture of an adenomyoepithelioma but which, on close examination, are found to contain foci of cellular atypia and increased mitotic activity. The two patterns of tumour exhibit the same clinical behaviour and should be distinguished from adenomyoepitheliomas, which are cytologically bland throughout. Received: 3 April 1997 / Accepted: 27 May 1997     

Imbalance between proliferation and apoptosis in the development of colorectal carcinoma

 To evaluate the relationship between cell proliferation and apoptosis in sporadic colorectal carcinogenesis, immunohistochemistry for proliferation-associated antigen Ki-67 and in situ end labelling for identifying apoptotic bodies were performed on paraffin sections from 59 adenomas and 22 carcinomas. These results were correlated with the expression of the proliferation and apoptosis modulators Bcl-2 and p53. Carcinomas showed increased proliferation and apoptosis compared with adenomas (P<0.0001, P<0.001, respectively). There were positive linear correlations between proliferation and apoptosis in adenomas and carcinomas (P<0.02, P<0.05, respectively). The proliferative rate increased significantly from mild to moderate, and from moderate to severe dysplasia (P<0.002, P<0.001, respectively). Apoptotic rate also increased in this sequence, but the increases did not reach statistical significance (both P>0.05). Expression of Bcl-2 was associated with lower apoptotic rate in adenomas (P<0.025) but not in carcinomas (P>0.25), whereas p53 expression was correlated with higher proliferative rate in both adenomas and carcinomas (P<0.01, P<0.05, respectively). An inverse relationship between Bcl-2 and p53 expression was seen in both adenomas and carcinomas (P<0.05, P<0.005, respectively). These data suggest that the normal balance between proliferation and apoptosis is disturbed in colorectal carcinogenesis, both being increased, but proliferation occurs in excess. Bcl-2 and p53 may each play a role in modulating cell apoptosis or proliferation during the development of colorectal carcinoma. Received: 23 March 1998 / Accepted: 7 July 1998     

乳腺癌17号染色体多体的临床病理意义

目的 探讨乳腺癌17号染色体多体异常的临床病理学意义.方法 回顾性分析200例乳腺癌荧光原位杂交结果,并分析17号染色体多体与年龄、核异型性、淋巴结转移以及HER2基因扩增、HER2蛋白表达的关系.结果 200例乳腺癌患者中表现为17号染色体多体异常的52例(26.0%),均为浸润性导管癌;占180例浸润性导管癌的52.8%.17号染色体多体与HER2基因扩增和HER2蛋白表达有关(均P=0.000),并且多体伴HER2基因扩增时也与HER2蛋白表达有关(P=0.001).多体和(或)多体伴HER2基因扩增都与乳腺癌癌细胞的高度异型性(P=0.010或P=0.012)及淋巴结转移有关(P=0.009或P=0.002).17号染色体多体或多体伴HER2基因扩增与乳腺癌患者的年龄无关(P=0.415或P=1.000).结论 17号染色体多体可能与乳腺癌患者的预后不良有关.     

Acinic cell carcinoma of the breast: an immunohistochemical and ultrastructural study

The clinicopathological features of six cases of breast carcinomas showing features of acinic cell differentiation, which are similar to those seen in homologous tumors of salivary glands, are presented. The patients, all women, were 35–80 years of age. One case recurred after 4 years, and in two cases axillary lymph-node metastases were found at the time of surgery. Histologically the tumors showed a microglandular pattern merging with solid areas. Cytologically, immunohistochemically, and ultrastructurally the tumors were very similar to cases of acinic cell carcinoma of the parotid gland.The differential diagnostic criteria with microglandular adenosis and carcinomas showing granular cytoplasm are discussed. It seems that acinic cell carcinomas of the breast have to be added to the long list of tumors that affect the salivary glands and can also arise in the breast. Received: 19 November 1999 / Accepted: 7 February 2000