Accumulation of genetic alterations during esophageal carcinogenesis

Using polymerase chain reaction amplification of microsatelliteregions in DNA from 11 epithelial dysplasias of the esophagusand 21 early squamous cell carcinomas, we were able to detectfrequent loss of heterozygosity (LOH) on chromosomes 3p21.3and 9q31 even in low-grade dysplasias. In contrast, we observedfrequent LOHs on chromosomes 9p22 and 17p13 (TP53 locus) onlyin high-grade dysplasias and carcinomas, but not in any low-gradedysplasias. Analysis of LOH at the same four chromosomal regionsIn DNA of five additional minimal carcinomas and accompanyingdysplastic lesions revealed loss of alleles at the loci on 3p21.3and 9q31 throughout various degrees of dysplasia and carcinoma;again, LOHs on 9q22 and 17p13 occurred only in high-grade dysplasiaand carcinoma in situ. Our results indicated that Inactivationof putative tumor suppressor genes on 3p21.3 and 9q31 may beearly genetic events during esophageal carcinogenesis, and thatadditional genetic alterations on 9p22 and 17p13 probably playroles in progression.     

Loss of heterozygosity in dysplasia and carcinoma of the gallbladder.

The loss or inactivation of genes at specific chromosomal loci is one of the important mechanisms during the tumor development in humans. To investigate the role of genetic alterations in the carcinogenesis of gallbladder carcinoma, 32 carcinoma cases and 11 dysplasia cases of gallbladder were analyzed for loss of heterozygosity (LOH) and microsatellite instability (MI) on chromosomal regions 3p, 5q, 8p, 9p, 13q, 17p, and 18q with 17 microsatellite markers. Loss of one allele was identified on chromosomes 5q (55%) and 17p (40%) in dysplasias and on chromosomes 3p (52%), 5q (66%), 9p (52%), and 17p (58%) in carcinomas. LOH on chromosomes 13q and 18q was frequent only in advanced stage (III and IV) carcinomas (40% and 31%, respectively). LOH on chromosome 17p was correlated with intranuclear p53 accumulation. LOH on multiple chromosomes was more frequent in advanced carcinomas with metastasis than in cases without metastasis (P < .05). A widespread MI was observed in only one case of carcinoma. We conclude that LOH on 5q is an early change of carcinogenesis in gallbladder and that LOH on 3p and 9p is related to the progression of gallbladder carcinoma LOH on 13q and 18q is likely to be a late event. LOH on 17p occurs not only in dysplasia but also increases during the subsequent stages. Accumulation of LOH may be associated with carcinogenesis of the gallbladder, but the role of MI may not be significant.     

Loss of heterozygosity at chromosomes 3, 6, 8, 11, 16, and 17 in ovarian cancer: correlation to clinicopathological variables

Tumor specimens from 78 epithelial ovarian cancer patients were examined for loss of heterozygosity (LOH) at 11 microsatellite markers at chromosomes 3p14.2, 6q27, 8p12, 11p15.5, 11q23.1-q24, 16q24.3, and 17p13.1, to evaluate the involvement, possible clustering, and prognostic significance of these lesions in the progression of the disease. The LOH analysis was performed on polymerase chain reaction (PCR)-amplified DNA from sections of paraffin-embedded tumor and normal tissue pairs. In addition to primary tumors, specimens of metastatic tissues were studied from 19 patients. In the combined results from primary and metastatic tumors, LOH frequencies varied between 31% (6q27) and 69% (17p13.1). Only LOH at chromosomal regions 3p14.2 (D3S1300), 11p15.5 (D11S1318), 11q23.3-q24 (D11S1340 and D11S912), 16q24.3 (D16S476 and D16S3028), and 17p13.1 (D17S938) was associated with an adverse disease course. Our results indicate that LOH at 17p13.1 occurs independently from the other chromosomal sites studied, and is an early event in ovarian tumorigenesis. The LOH at 16q24.3, 11q23.3/q24, and 11p15.5 seems to occur later. The LOH at 11p15.5 and 11q23.3 was associated with reduced cancer-specific survival time; therefore, the studied markers could be located close to genes with influence on patient survival. Of the studied chromosomal regions, the most important tumor suppressor genes involved in the evolution of ovarian cancer appear to be located on chromosomes 11, 16, and 17. The genetic heterogeneity observed in primary and metastatic specimens demonstrates that there are multiple pathways involved in the progression of ovarian cancer.     

喉癌p16区域的杂合性丢失和微卫星序列不稳定性分析

目的 缩小喉癌抑癌基因的寻找范围,探讨Ｐ１６基因在喉癌发生中的作用。方法 选择Ｐ１６基因附近５个微卫星多态标记对６０例喉癌进行杂合性丢失和微卫星序列不稳定性分析。结果 ５个标记在喉癌中杂合性丢失频率均不高,最高仅达２３．１％,但２个标记的微卫星序列不稳定性的频率较高,其中示记微卫星序列恶性循环频率高达４６．１％。结论 提示Ｐ１６基因在喉癌的发生中不以缺失为主,在Ｄ９Ｓ１７５２附近可能存在参与喉癌演     

LOH at the sites of the DCC, APC, and TP53 tumor suppressor genes occurs in Barrett's metaplasia and dysplasia adjacent to adenocarcinoma of the esophagus

Barrett's esophagus carries a 30- to 100-fold increased risk of adenocarcinoma, which is thought to develop via a metaplasia-dysplasia-carcinoma progression. A common genetic abnormality detected in Barrett's adenocarcinoma is loss of heterozygosity (LOH) at the sites of known or putative tumor suppressor genes, of which there are at least 9 associated with esophageal adenocarcinoma. The aim of this study was to identify at which histological stage of carcinogenesis LOH at these sites occur. Microdissection of multiple paraffin-embedded tissue blocks from 17 esophagogastrectomy specimens of adenocarcinoma arising in Barrett's esophagus yielded areas of metaplasia, low-, intermediate- and high-grade dysplasia, and carcinoma. LOH analysis of microdissected tissues was performed using a double polymerase chain reaction technique with 11 microsatellite primers shown previously to have LOH in at least 30% of esophageal adenocarcinomas. Identical LOH was detected in premalignant and malignant tissues in 4 of 17 patients, and was located at 5q21-q22 (D5S346 primer), 17p11.1-p12 (TCF2 primer), 17p13.1 (TP53 primer), 18q21.1 (detected in colon cancer tumor suppressor gene [DCC] primer), and 18q23-qter (D18S70 primer). These results suggest that LOH at the sites of the DCC, adenomatous polyposis coli (APC), and TP53 tumor suppressor genes occur before the development of adenocarcinoma in Barrett's esophagus, and so merit further study as potential biomarkers of neoplastic progression in patients with Barrett's esophagus undergoing endoscopic and histological surveillance.     

食管鳞癌及其前驱病变基因杂合子缺失的研究

目的 通过对食管黏膜高级别上皮内瘤变和鳞状细胞癌中的等位基因杂合子缺失(LOH)的检测,以期发现与食管鳞状细胞癌关系密切的抑癌基因。方法 应用显微切割,PCR扩增、凝胶电泳、放射自显影等技术,对照分析正常体细胞、食管鳞状上皮高级别上皮内瘤变和食管鳞状细胞癌组织中LOH的变化,并就各位点杂合子缺失率与患者的临床病理参数分别进行单因素分析。结果 高级别上皮内瘤变中7个位点的LOH依次为D13S802(40%)、D9S171(33%)、D13S267(320%)、D13S221(31%)、D9S942(30%)和D17S520(240%),而D17S1798在本组上皮高级别上皮内瘤变中未发现杂合子缺失。在食管鳞状细胞癌组织中,上述7个位点的LOH率依次为D13S267(71%),D13S802(58%),D17S520(55%)、D13S221(45%)、D9S942(43%)、D9S171(33%)和D17S1798(11%)。应用SPSS软件对7个微卫星序列的等位基因LOH率与患者的病理学分级、临床病理分期及是否有淋巴结转移进行单因素分析,差异均无显著性(P>0.05)。结论 (1)从正常黏膜到上皮内瘤变再到食管鳞癌的发生过程中,同时伴随基因异常的逐步积累。(2)13q12.12上的D13S802附近可能存在着主要与食管鳞状细胞癌早期发生有关的抑癌基因。(3)13q12.3上的D13S267附近、17p13.1上的D17S520和17p13.3上的D17S1798附近的基因可能与食管     

Extensive and divergent chromosomal losses in squamous and spindle-cell components of esophageal sarcomatoid carcinoma

Sarcomatoid carcinoma of the esophagus is an unusual type of squamous cell carcinoma (SCC) with a variable component of sarcomatoid spindle cells (SA). The loss of heterozygosity (LOH) involving multiple cancer-associated chromosomal arms has been reported to have a concerted, rather than an individual, effect on tumor progression. In order to delineate the role of LOH in the evolution of a biphasic tumor, the carcinoma in situ (CIS), invasive squamous cell carcinoma (ISCC), and SA components from a sarcomatoid carcinoma of the esophagus were compared for their clonality and extent of LOH. Forty microsatellite markers on the cancer-associated chromosomes, 3p, 4p, 5q, 8p, 9p, 13q, 17p, and 18q, were used for the polymerase chain reaction-based LOH analysis. All eight sarcomatoid carcinomas tested revealed extensive LOHs, involving an average of seven chromosomal arms. All CIS, ISCC, and SA components carried not only a high-level primary LOH (mean chromosomal involvement, 5.3) in common but also a low-level secondary LOH (mean chromosomal involvement, 1.8) in disparity. Interestingly, more secondary LOHs were always burdened in the CIS (four cases) rather than the matched ISCC. SA had a greater (four cases), equal (one case), or fewer (one case) number of secondary LOHs than ISCC. Given that excessive chromosomal losses may confer a disadvantage for tumor growth or a benefit for a metaplastic transformation, these results suggest that the multidirectional differentiation of a SCC precursor is stimulated by extensive and divergent LOHs acquired at the initial or early stages, and a precursor burdened with excessive LOH either remains in CIS or expands as a SA component.     

Molecular alterations of Barrett's esophagus on microdissected endoscopic biopsies

Alterations in proto-oncogenes and tumor suppressor genes play a role in the sequence from Barrett's metaplasia to esophageal adenocarcinoma. The present study aims to ascertain whether molecular abnormalities take place in Barrett's metaplasia and low-grade dysplasia and to correlate them with the histological features of the esophageal mucosa. Forty-one formalin-fixed, paraffin-embedded endoscopic esophageal biopsies were classified according to the type of metaplastic changes (noncolumnar fundic and cardial metaplasia; columnar metaplasia, with and without intestinal features). After microdissection samples were examined for loss of heterozygosity (LOH) using polymorphic markers on 5q (D5S82), corresponding to APC (adenomatous polyposis coli) gene, 13q (CA repeat in intron 2 position 14815 to 14998 of the retinoblastoma gene), 17p (D17S513) corresponding to p53 locus, and for p53 mutations. Molecular alterations including LOH, allelic imbalance, and microsatellite instability could be detected in all types of metaplastic changes and sporadically in the squamous epithelium adjacent to the metaplastic tissue. Molecular alterations involving microsatellites D5S82 and the CA repeat inside the retinoblastoma gene were more frequent in nonintestinal metaplasia whereas those involving the p53 locus took place in columnar intestinal metaplasia and in low-grade dysplasia. Clonal changes were demonstrated in different metaplastic areas in three patients. Genetic alterations comprising LOH and microsatellite instability characterize Barrett's mucosa and appear related to the type of metaplastic change. Some of them precede the development of intestinal metaplasia, suggesting that genetic alterations take place earlier than previously thought.     

Genetic mechanisms in esophageal carcinogenesis: Frequent deletion of 3p and 17p in premalignant lesions

Although dysplasia of the esophagus is thought to be the precursor lesion of esophageal squamous cell carcinoma (ESC), the sequence of genetic events during esophageal carcinogenesis is unclear. Using the polymerase chain reaction, we examined allelic losses at microsatellite loci in DNAs isolated from 106 lesions among 32 patients with ESC. Allelic losses on 3p or 17p occurred frequently even in dysplastic lesions (9 of 21 and 13 of 24 samples, respectively) including lesions with mild dysplasia (3p, 4 of 10 samples; 17p, 6 of 14 samples, respectively), and allelic losses on these chromosomal arms were also observed in cancerous tissues. We also detected allelic losses of the short and long arms of chromosome 9 at a low frequency in lesions with mild dysplasia and often in lesions with severe dysplasia and in intraepithelial cancers. Our results suggested that inactivation of tumor suppressor genes on 3p and 17p occurs at a very early stage of esophageal carcinogenesis and that genes on 9p and 9q are likely to play important roles in malignant changes. Comparison of the genetic alterations in precancerous dysplastic lesions with those in carcinomas supports the idea that ESC arises from the dysplastic lesion. Genes Chromosom Cancer 15:165–169 (1996). © 1996 Wiley-Liss, Inc.     

Chromosome bands 3p14.2, 9p21, and 13q14 are frequently deleted in roentgenographically occult bronchogenic squamous cell carcinoma of the lung

Roentgenographically occult bronchogenic squamous cell carcinomas are early lung cancers that localize mainly within the bronchial wall and are thought to be a good model for elucidating chromosomal alterations during lung cancer progression. In this study, we analyzed allelic losses on chromosome regions 1p36, 3p14.2, 9p21, 10q25.3–q26.1, 13q14.12–q14.2, and 16q24.1–q24.2, in which there are putative tumor suppressor genes that may play roles in lung carcinogenesis. Forty-five cases with roentgenographically occult bronchogenic squamous cell carcinoma (ROC) and 47 cases of bronchogenic carcinoma with abnormal shadows (roentgenographically nonoccult bronchogenic squamous cell carcinoma [RNOC]) were examined. Highly frequent LOHs in both ROCs and RNOCs were observed in chromosome regions 3p14.2, 9p21, and 13q14.1–q14.2. LOHs were more frequently observed in RNOCs than in ROCs at two loci: 10q25.3–q26.1 and 16q24.1–q24.2. These results suggested that (1) putative tumor suppressor genes exist on 3p14.2, 9p21, 10q25.3–q26.1, 13q14.12–q14.2, and 16q24.1–q24.2, which may play important roles in lung carcinogenesis; (2) mutations in genes at 3p14.2, 9p21, and 13q14.12–q14.2 represent rather early events in lung carcinogenesis; and (3) mutations in genes on 10q25.3–q26.1 and 16q24.1–q24.2 represent rather late events. Genes Chromosomes Cancer 23:367–370, 1998. © 1998 Wiley-Liss, Inc.     

A high frequency of allelic loss in oral verrucous lesions may explain malignant risk

Verrucous carcinoma (VC), a variant of squamous cell carcinoma (SCC), is distinct from SCC in morphology and behavior. The underlying genetic changes involved in the development of VC and its precursor verrucous hyperplasia (VH) are unknown. This study determined whether chromosomal regions frequently lost during the development of SCC are also lost in the VH/VC variant. Twenty-five VH and 17 VC were analyzed for loss of heterozygosity (LOH) at 19 loci on 7 chromosome arms using microsatellite analysis. These data were compared with those from 47 reactive hyperplasias, 92 dysplasias (54 low- and 38 high-grade), and 41 SCCS: The results showed that VC/VH shared many of the losses present in dysplasia/SCC but differed in two aspects. First, VC/VH showed early acquisition of loss, compared with a gradual accumulation of losses from dysplasias to SCC. The LOH pattern of VH was similar to that of high-grade dysplasia and sharply different from reactive hyperplasia. The loss in VH often involved multiple arms (in 60% of VH vs 0% of reactive lesions). Only a marginal elevation of loss was observed at 9p (p = 0.06) and 4q (p = 0.05) from VH to VC because of the high degree of loss already present in VH. Second, a strikingly lower frequency of loss at 17p was noted in VH/VC compared with dysplasia/SCC and may indicate human papillomavirus (HPV) involvement. The finding of high-risk LOH profiles in VH may partly account for the high-progression risk seen for VH and also has potentially important clinical implications. The difficult pathological diagnosis of VH/VC from reactive hyperplasia frequently requires repeated biopsies and results in delay in diagnosis and significantly increased mortality/morbidity. Microsatellite analysis might facilitate this differential diagnosis.     

Microsatellite instability in preinvasive and invasive head and neck squamous carcinoma.

To investigate the extent and significance of microsatellite instability in head and neck carcinogenesis we analyzed DNA extracted from normal squamous epithelium, severe dysplasia, and corresponding carcinoma specimens from 20 patients by multiplex polymerase chain reaction. Loci on chromosomes 3p, 5p, 5q, 8p, 9p, 9q, 11q, 17p, 17q, 18p, 18q were selected for analysis. Our results show that three of the dysplasias (15.0%) and six of the invasive carcinoma (30.0%) manifested instability at multiple loci. Two of the dysplastic lesions had identical alterations in the corresponding carcinomas and one showed instability differences in only two of eight loci. Normal squamous epithelium lacked microsatellite instability. No apparent association between smoking, alcohol use, or family history of cancer and instability was found in this small cohort. Invasive carcinomas with instability were relatively more poorly differentiated and had a higher stage and a high proliferative fraction. Our study indicates that microsatellite instability is 1) noted in a small subset of dysplastic lesions of head and neck squamous epithelium and 2) present in approximately one-third of invasive lesions, usually with aggressive characteristics, and may clinically be a late event associated with tumor progression.     

Expression of cell cycle regulatory proteins in the multistep process of oesophageal carcinogenesis: stepwise over-expression of cyclin E and p53, reduction of p21(WAF1/CIP1) and dysregulation of cyclin D1 and p27(KIP1)

AIMS: Cell cycle regulatory proteins were analysed by immunohistochemistry in order to clarify how their expression changes with the degree of atypia as oesophageal surface squamous epithelium progresses from normal mucosa, through reactive change, low-grade dysplasia, and high-grade dysplasia to mucosal invasive carcinoma. METHODS AND RESULTS: Immunostaining for cyclin D1, cyclin E, p21, p27, p53 and Ki67 proteins was performed using 22 normal mucosa, 17 reactive change, 22 low-grade dysplasia, 15 high-grade dysplasia and 22 mucosal invasive carcinoma specimens. Normal mucosa, low-grade dysplasia and high-grade dysplasia samples were taken from patients without any oesophageal invasive carcinoma by endoscopic biopsy or endoscopic mucosal resection, and reactive change and mucosal invasive carcinoma were obtained from oesophagectomy material. Stepwise over-expression of cyclin E (P < 0.0001) and p53 (P < 0.0001), reduction of p21 (P=0.0189) and dysregulation of cyclin D1 and p27 were observed in the multistep process of oesophageal carcinogenesis. Significant differences in expression of p27 (P < 0.0001), p53 (P=0.0299) and Ki67 (P=0.0101) were observed between reactive change and low-grade dysplasia. Furthermore, expression of cyclin D1, cyclin E, p27 and p53 in mucosal invasive carcinoma were significantly different from those in high-grade dysplasia (P=0.0079, P=0.0237, P=0.0042 and P= 0.0299, respectively). CONCLUSIONS: Cell cycle regulatory proteins, cyclin E, p53 and p21 show stepwise over-expression or reduction with progression of oesophageal carcinogenesis, correlating with the increased cell proliferation observed with Ki67 labelling. We conclude that immunohistochemical analysis for p27, p53 and Ki67 is practically useful for the discrimination between low-grade dysplasia and reactive change. Cyclin D1, cyclin E, p27 and p53 help to distinguish high-grade dysplasia from mucosal invasive carcinoma.     

Molecular analysis of oral lichen planus. A premalignant lesion?

Oral lichen planus (OLP) is a common mucosal condition that is considered premalignant by some, although others argue that only lichenoid lesions with dysplasia are precancerous. To address the question of whether OLP without dysplasia is premalignant, we used microsatellite analysis to examine 33 cases of OLP for allelic loss at nine loci located on chromosomes 3p, 9p, and 17p. Loss of heterozygosity (LOH) on these three arms occurs frequently in oral tumors, and the presence of these alterations in premalignant lesions suggests that they may play an important role in tumor progression. Results were compared with those observed in oral dysplasias (10 mild, 11 moderate, 16 severe/carcinoma in situ), 22 oral squamous cell carcinomas, and 29 reactive lesions. LOH was present in 6% of OLP, 14% of reactive lesions, 40% of mild dysplasia, 46% of moderate dysplasia, 81% of severe dysplasia/carcinoma in situ, and 91% of squamous cell carcinomas. LOH was detected on only a single arm in OLP and reactive lesions but occurred on more than one chromosome in dysplasia and cancer, and the frequency of this multiple loss correlated significantly with increasing degrees of dysplasia and progression into squamous cell carcinoma (P = 0.0028). Although these findings do not support OLP as a lesion at risk for malignant transformation, such results need to be confirmed by use of other genetic markers as OLP may undergo malignant transformation through genetic pathways different from those of oral dysplasia.     

Comparison of losses of heterozygosity and replication errors in primary colorectal carcinomas and corresponding liver metastases

In order to investigate genetic alterations specific to liver metastases of colorectal carcinomas, losses of heterozygosity and replication errors have been compared in 15 cases of primary colorectal carcinoma and in the corresponding metastatic liver tumours. Fifteen microsatellite markers located on 13 different chromosomal arms were used in the study. The LOH patterns of the primary and the metastatic tumours were identical in eight cases and showed differences in seven cases. Areas of deletion predominantly or completely common to the colorectal and the metastatic tumour were detected on chromosomes 5q, 8p, 17p, 18q, and 22q. Preferential loss in metastatic tumours was observed on chromosomal arm 3p. Replication errors were found in four primary tumours and in three of the corresponding secondaries. A replication error phenotype specific to a metastasis was not observed. Copyright © 1999 John Wiley & Sons, Ltd.     

p63基因在肺癌组织中的表达

目的研究肺鳞状细胞癌、腺癌、大细胞肺癌、小细胞肺癌以及淋巴结或肺内转移性肿瘤标本组织中p63基因的mRNA转录因子和蛋白表达水平,探讨p63基因表达与其定位在3q 27-q29区域改变的关系.方法采用cDNA微阵列技术同时检测72例不同病理组织学类型的原发性肺癌(包括鳞状细胞癌、腺癌、大细胞癌、小细胞癌)和肺癌肺内转移及淋巴结转移灶内的p63基因mRNA水平.另外,利用组织芯片技术构建150例原发性肺癌石蜡包埋标本组织芯片,采用免疫组织化学LSAB法检测p63基因蛋白表达情况.同时应用比较基因组杂交(CGH)技术对70例原发性肺癌标本进行了3号染色体长臂改变的分析.结果p63mRNA转录因子在肺鳞状细胞癌标本表达明显增强,与腺癌、大细胞癌、小细胞癌相比增多10倍以上.肺癌转移灶内p63基因mRNA表达水平明显高于其相对应的原发性灶,差异有统计学意义(P＜0.001).免疫组织化学染色结果显示肺鳞状细胞癌阳性表达率为94.64%;腺癌是1.79%;4例大细胞肺癌中2例为阳性染色;但所有小细胞肺癌标本免疫组织化学染色均为阴性.pT1分期肺癌的p63基因蛋白表达阳性率与pT2分期肺癌相比有统计学差异(P＜0.05).比较基因组杂交结果发现肺鳞状细胞癌3号染色体长臂27-29区域有显著的扩增,腺癌表现为缺失.鳞状细胞癌p63基因的表达增强与3q27-q29区域的显著扩增有明显正相关性(P＜0.000 1),说明定位于3号染色体长臂27-29区域的p63基因的拷贝有明显的扩增.结论p63mRNA转录因子和蛋白在肺鳞状细胞癌较其他肿瘤表达显著增高,转移灶高于原发灶;肺鳞癌p63表达增强与3号染色体长臂3q27-q29区域的扩增显著相关.     

Clinicopathological significance of loss of heterozygosity in intestinal- and solid-type gastric carcinomas: a comprehensive study using the crypt isolation technique.

The clinicopathological significance of loss of heterozygosity (LOH) in gastric carcinoma remains poorly understood. We and other researchers have previously demonstrated that LOH is fairly common in intestinal- and solid-type gastric carcinomas, but rare in diffuse-type tumors. In this study, we investigated the relationship between clinicopathological variables and LOH status in intestinal- and solid-type gastric carcinomas. The crypt isolation technique was utilized to analyze LOH at 1p36, 3p14, 4p15, 5q21-22, 8p11-12, 9p21, 13q22, 17p13.1 18q21 and 22q13.31 in 113 intestinal- and solid-type gastric carcinomas using a polymerase chain reaction assay. Immunostaining with D2-40 and Elastica van Gieson staining were used to detect lymphatic invasion and vessel invasion, respectively. High LOH rates (49-71%) were observed in all chromosomal regions tested. 1p36 loss was significantly associated with advanced tumors and lymph node metastasis. 8p11-12 loss was significantly associated with lymph node metastasis, lymphatic invasion, and vessel invasion. 17p13.1 (TP53) loss was significantly associated with vessel invasion. 22q13.31 loss was significantly associated with advanced tumors, lymph node metastasis, lymphatic invasion, vessel invasion and late TNM stage. No significant associations were observed between LOH at other chromosomal regions and aggressive behaviors. In addition, significantly higher LOH rates at 1p36, 9p21, 18q21 and 22q13.31 were observed in cardiac tumors compared with noncardiac tumors. These results suggest that in intestinal- and solid-type gastric carcinomas, LOH on 3p14, 4p15, 5q21-22, 9p21, 13q22 and 18q21 is associated with carcinogenesis, while LOH on 1p36, 8p11-12, 17p31.1 and 22q13.31 is associated with tumor progression.     

A detailed deletion map of chromosome 20 in human oral squamous cell carcinoma

Loss of heterozygosity (LOH) on the long arm of chromosome 20 (20q) has been detected in several human cancers. However, little is known about LOH on chromosome 20 in oral squamous cell carcinoma (OSCC). To determine which loci of chromosome 20 were involved in OSCC tumorigenesis, 41 cases of OSCC were examined for LOH state on chromosome 20 at 17 microsatellite loci by PCR-LOH assay. LOH occurred in 41.5% of tumors in at least one locus. Among the 17 loci, D20S48 on 20p11.2 and RPN2 on 20q12-13.1 exhibited higher frequencies of LOH, 27.6% and 31.4%, respectively. The LOH incidence was significantly higher in tumors in which the primary site was on gingiva compared with other oral sites (p=0.012). Our results indicate that allelic deletions on 20q12-13.1 and 20p11.2 may play roles in OSCC carcinogenesis, and suggest that allelic deletions on 20q might have some relation with the primary site of OSCC.     

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.