鼻咽癌染色体16q22-24遗传不稳定性的研究

目的：研究鼻咽癌染色体16q22-24的遗传稳定性。方法：用染色体16q22-24上的8对微卫星多态性标记分析50例鼻咽癌的杂合性缺失（loss of heterozygosity,LOH）与微卫星不稳定性（microsatellite instability,MSI)。结果：至少一个位点发生LOH的肿瘤占48％（24／50）,MSI的发生率为18％（9／50）。但这些变化均散在分布,未见高频共同缺失区和微卫星不稳定区;其变化在早期（Ⅰ/Ⅱ期）和晚期（Ⅲ/Ⅳ期）病人之间有显著性差异（P＜0．05）。结论：染色体16q22－24区的遗传不稳定性的变化可能与鼻咽癌的发病有关,该区是否存在鼻咽癌相关基因有待进一步探讨。     

宫颈癌患者基因组遗传不稳定性分析

目的 研究中国宫颈癌高发区宫颈癌患者基因组遗传不稳定性改变，为寻找宫颈癌相关内源因子提供依据。方法 从GenBank中选取8对微卫星DNA引物，采用PCR-变性PAGE-银染方法检测50例宫颈癌(来自高发区)活检组织及其对照(同病例血液)样品的杂合性丢失(LOH)和微卫星不稳定(MI)。结果 LOH总检出率为66％(33／50)，其中，D18S474(染色体18q21)LOH达40．5％；染色体3p21．2—3p21．3中微卫星位点D3S1478，LOH达31．7％；并且在原位癌与浸润癌中，LOH分布也有一定差异。MI在宫颈癌患者基因组中仅存在少数微卫星位点，总的发生率较低，为8％(4／50)。结论 除高危型人乳头瘤病毒(HPVhr)感染外，细胞内源基因的改变在宫颈癌发生发展过程中也起着重要作用。高频LOH位点18q21 D18S474、3p21．2-3p21．3 D3S1478可能存在潜在的宫颈癌抑癌基因。     

The molecular genetics of cervical carcinoma.

In the pathogenesis of cervical carcinoma there are three major components, two of them related to the role of human papillomaviruses (HPV). First, the effect of viral E6 and E7 proteins. Second, the integration of viral DNA in chromosomal regions associated with well known tumour phenotypes. Some of these viral integrations occur recurrently at specific chromosomal locations, such as 8q24 and 12q15, both harbouring HPV18 and HPV16. And third, there are other recurrent genetic alterations not linked to HPV. Recurrent losses of heterozygosity (LOH) have been detected in chromosome regions 3p14-22, 4p16, 5p15, 6p21-22, 11q23, 17p13.3 without effect on p53, 18q12-22 and 19q13, all of them suggesting the alteration of putative tumour suppressor genes not yet identified. Recurrent amplification has been mapped to 3q+ arm, with the common region in 3q24-28 in 90% of invasive carcinomas. The mutator phenotype, microsatellite instability, plays a minor role and is detected in only 7% of cervical carcinomas. The development of cervical carcinoma requires the sequential occurrence and selection of several genetic alterations. The identification of the specific genes involved, and their correlation with specific tumour properties and stages could improve the understanding and perhaps the management of cervical carcinoma.     

FHIT基因微卫星变异与宫颈癌关系的分析

[目的]探讨FHIT基因微卫星变异与宫颈癌的关系。[方法]选取FHIT基因的两个微卫星多态标记,采用聚合酶链反应法（PCR）对50例宫颈癌及40例宫颈上皮内瘤样病变（CIN）组织进行杂合性丢失（LOH）和微卫星不稳定性（MI）的检测。[结果]在D3S1234位点上宫颈癌的LOH发生率为46%（23/50）,CIN的LOH发生率为40%（16/40）,宫颈癌与CIN的LOH发生率差异无统计学意义（P〉0.05）,宫颈癌的MI发生率为18%（9/50）,CIN的MI发生率为12.5%（5/40）,差异无统计学意义（P〉0.05）;在D3S4103位点上宫颈癌的LOH发生率为40%（20/50）,CIN的LOH发生率为37.5%（15/40）,差异无统计学意义（P〉0.05）,宫颈癌的MI发生率为14%（7/50）,CIN的MI发生率为7.5%（3/40）,差异无统计学意义。但宫颈癌在两位点上LOH和MI发生频率均高于CIN,且高级别CIN发生率高于低级别CIN。[结论]FHIT基因的变异发生在宫颈癌变的晚期;FHIT基因的LOH与MI对于宫颈癌的筛查、早期诊断及判断预后可能具有临床实用价值。     

High frequency of loss of heterozygosity in vulval intraepithelial neoplasia (VIN) is associated with invasive vulval squamous cell carcinoma (VSCC).

Vulval intraepithelial neoplasia (VIN) is thought to be the premalignant phase of human papillomavirus (HPV)-associated vulval squamous cell carcinoma (VSCC). Various molecular events have been suggested as markers for progression from VIN to VSCC, but loss of heterozygosity (LOH) in vulval neoplasia has rarely been studied in this context. We performed LOH analysis by polymerase chain reaction (PCR) amplification of polymorphic microsatellite markers at 6 chromosomal loci (17p13-p53, 9p21-p16, 3p25, 4q21, 5p14 and 11p15). The presence of HPV was assessed using consensus PCR primers and DNA sequencing. To examine any association between LOH and the presence of invasive disease, we analyzed 43 cases of lone VIN III, 42 cases of lone VSCC and 21 cases of VIN with concurrent VSCC. HPV DNA was detected in 95% of lone VIN III samples and 71% of lone VSCC samples. Fractional regional allelic loss (FRL) in VIN associated with VSCC was higher than in lone VIN (mean FRL 0.43 vs. 0.21, p < 0.005). LOH at 3p25 occurred significantly more frequently in HPV-negative VSCC than in HPV-positive VSCC (58% vs. 22%, p < 0.04). These data suggest that genetic instability in VIN, reflected by LOH, may increase the risk of invasion. In addition, molecular events differ in HPV-positive and -negative VSCC and 3p25 may be the site of a tumor suppressor gene involved in HPV-independent vulval carcinogenesis.     

Cytogenetic alterations in ovarian clear cell carcinoma detected by comparative genomic hybridisation

Ovarian clear cell carcinoma (OCCC) accounts for a small but significant proportion of all ovarian cancers and is a distinct clinical and pathological entity. It tends to be associated with poorer response rates to chemotherapy and with a worse prognosis. Little is known about possible underlying genetic changes. DNA extracted from paraffin-embedded samples of 18 pure OCCC cases was analysed for genetic imbalances using comparative genomic hybridisation (CGH). All of the 18 cases showed genomic alterations. The mean number of alterations detected by CGH was 6 (range 1-15) indicating a moderate level of genetic instability. Chromosome deletions were more common than amplifications. The most prominent change involved chromosome 9 deletions in 10 cases (55%). This correlates with changes seen in other epithelial ovarian cancers. This deletion was confirmed using microsatellite markers to assess loss of heterozygosity (LOH) at four separate loci on chromosome 9. The most distinct region of loss detected was around the IFNA marker at 9p21 with 41% (11 out of 27 cases) LOH. Other frequent deletions involved 1p (five out of 18; 28%); 11q (four out of 18; 22%) and 16 (five out of 18; 28%). Amplification was most common at chromosome 3 (six out of 18; 33%); 13q (four out of 18; 22%) and 15 (three out of 18; 17%). No high-level amplifications were identified. These features may serve as useful prognostic indicators in the management of OCCC.     

Genetic deletion and human papillomavirus infection in cervical cancer: loss of heterozygosity sites at 3p and 5p are important genetic events.

"High-risk" human papillomavirus (HPV) types 16/18 are recognized as being associated with cervical cancer. We have already reported frequent loss of heterozygosity (LOH) at 3p, 3q, 4q, 5p and 5q in primary cervical cancer, the frequency at these sites ranging from 31.0 to 56.3%. The present analysis deals with these frequent-deletion sites in relation to HPV infection. HPV frequency, as determined by PCR and by Southern-blot, was 87.0%. Out of 45 HPV-positive tumours, 26 (57.8%) were "high-risk" HPV-16/18-positive, with HPV type 16 predominant (24 of 26). Among these 24, 14 (58.3%) tumours had HPV-16 DNA integrated with the host genome. LOH on 3p revealed significant association with HPV-16/18 infection; 64.0% of LOH at 3p was in HPV16/18-positive tumours, vs. 23.3% in the tumours that did not reveal the presence of HPV16/18. On the other hand, 78.6% of LOH at 5p, which was the most frequent (56.3%), was in tumours without HPV16/18 infection, vs. 43.7% in tumours that had HPV 16/18 infection, suggesting independence of HPV 16/18 infection. At other sites, LOH did not differ, irrespective of the presence or absence of "high-risk" HPV infection.     

Mapping common deleted regions on 5p15 in cervical carcinoma and their occurrence in precancerous lesions

Previous studies have shown that the short arm of chromosome 5 (5p) exhibit frequent genetic changes in invasive cervical carcinoma (CC), and that these changes arise early during the carcinogenesis, in precancerous lesions. These data therefore suggest that loss of candidate tumor suppressor genes located on 5p is associated with the development of CC. However, the precise location of 5p deletions is not known. We performed a detailed deletion mapping of 5p in 60 cases of invasive CC. We found that 60% of the tumors exhibit a 5p loss of heterozygosity (LOH). The patterns of LOH allowed us to identify two minimal regions of deletions, one at 5p15.3 spanning a 5.5 cM genetic distance and a second site of 7 cM at 5p15.2-15.3. In addition, we also identified 5p deletions in 16% lesions of high-grade cervical intraepithelial neoplasia (CIN). 5p LOH was found in 63% of HPV 16 positive tumors, while only 33% tumors with other HPV-types had 5p LOH. The differences in frequency of 5p LOH between tumors harboring HPV16 in combination with other HPV types and tumors harboring HPV16 DNA alone were significantly higher, suggesting a synergistic effect of high-risk types in causing genomic instability. These findings implicate the presence of tumor suppressor gene(s) on 5p relevant to CC tumorigenesis.     

The supplementary diagnostic power of selected immunohistochemical, molecular genetic and infective parameters in epithelial hyperplastic laryngeal lesions

OBJECTIVES: MIB-1 and p53 protein expression, loss of heterozygosity (LOH), microsatellite instability (MSI) of di- and mononucleotide repeats, and HPV status were tested for their potential to characterize different stages of epithelial hyperplastic laryngeal lesions (EHLL). METHODS: Thirty-two EHLL were reclassified according to the Ljubljana classification into simple (SH), abnormal (AbH), atypical hyperplasia (AtH) and carcinoma in situ, and investigated by immunohistochemical methods, PCR and direct sequencing analysis. RESULTS: MIB-1 increased with progressive grades of EHLL, whereas p53 protein expression was distinctive only between SH and AbH. LOH showed increasing frequency with grades of the lesions, but the distribution of altered loci (9p, 9q, 10q, 11q, 17p) was not qualified to differentiate between the stages. MSI was detected in SH, AbH and AtH without clear correlation to histopathological grading. HPV infection occurred mostly in SH and AbH (both: 66.7%). CONCLUSION: MIB-1 labeling and allelic loss could assist histopathological diagnosis in the entire spectrum of EHLL, whereas the MSI results point to a genetic instability of the laryngeal mucosa in general and are therefore not helpful in the distinction of different stages of EHLL. However, future molecular genetic analyses should consider more late events of laryngeal carcinogenesis to improve their diagnostic potential. Furthermore, our results indicate that nonrisky and risky EHLL could probably be caused by different exogenous factors.     

Chromosome 6p21.2, 18q21.2 and human papilloma virus (HPV) DNA can predict prognosis of cervical cancer after radiotherapy

Loss of heterozygosity (LOH) is one of the most important mechanisms for inactivation of tumor-suppressor genes. Studies of LOH in patients with cervical carcinoma have reported a high frequency of LOH on 3p21.3, 6p21.2, 17p13.1, and 18q21.2. Our study explored whether p53 status, human papilloma virus (HPV), and LOH on chromosome 3p21.3, 6p21.2, 17p13.1, and 18q21.2 are associated with treatment outcome in 65 patients with cervical cancer after radiotherapy. Tumors and normal DNA were analyzed by polymerase chain reaction (PCR) for genetic losses at 10 polymorphic microsatellite loci. The presence of HPV and its type were analyzed by PCR-based assay using the consensus primers for E6, E7, and L1 region. Mutations of the p53 gene were identified by a single-strand conformation polymorphism analysis. Chromosomes 3p21.3, 6p21.2, 17p13.1, and 18q21.2 were involved in the LOH in 23.1%, 41.5%%, 33.8%, and 23.1% of the tumors in our study, respectively. HPV-positive tumors were found in 73.8% of the patients and p53 mutation in 10.8%. The patients with LOH on chromosome 6p21.2 and 18q21.2 survived significantly shorter compared with those without LOH on chromosome 6p21.2 and 18q21.2 in both the overall survival (P = 0.006 and P = 0.007) and the disease-free survival (P = 0.005 and P = 0.008). The HPV-negative patients survived significantly shorter compared with the HPV-positive patients in both the overall survival (P = 0.01) and the disease-free survival (P = 0.04). According to multivariate analysis, HPV status (P = 0.0004, P = 0.01), LOH on 6p21.2 (P = 0.006, P = 0.02), and LOH on 18q21.2 (in both P = 0.01) is a significant predictor of both overall and disease-free survival time. The results of our study suggest that absence of HPV infection, LOH on 6p21.2, and LOH on 18q21.2 are the most important determinants of outcome of patients with cervical carcinoma after radiotherapy.     

Relationship between Microsatellite Alterations of RASSF1A Gene and Development of Cervical Carcinoma

Objective： To explore the relationship between microsatellite alterations of RASSFIA gene and the development of cervical carcinoma, and its relationship with HPV16 infection. Methods： Two sites of microsatellite polymorphism of RASSFIA gene were selected. Polymerase chain reaction （PCR） technique was used to detect LOH and MSI in 50 cases of cervical carcinoma and 40 cases of cervical intraepithelial neoplasia （CIN）, and to detect the infection state of HPV16. Results： At D3S1478 and D3S4604, the LOH rates of cervical carcinomas were 32.6% （14/43） and 48.9% （23/47）, the MSI rates were 14% （6/43） and 19.1% （9/47）, respectively. The LOH rates of CINs were 31.4% （11/35） and 39.5% （15/38）, the MSI rates were 11.4% （4/35） and 15.8% （6/38）, respectively. There were no significant differences between cervical carcinomas and CINs in respect to their positive rates of LOH and MSI at D3S1478 and D3S4604 （P〉0.05）. There were significant differences in LOH rates at D3S1478 and D3S4604 between the stage Ⅰ-Ⅱ and Ⅲ-Ⅳ cervical carcinomas and between the well/moderately differentiated cervical carcinomas and the poorly differentiated cervical carcinomas （P〈0.05）. The positive rates of LOH and MSI for CIN Ⅲ and noninvasive cervical carcinomas were higher than those in CIN Ⅰ-Ⅱ. The rates of infection of HPV16 in cervical cancer was obviously higher than that in CIN and in normal cervical tissues （P〈0.05）, and the incidence of LOH of RASSFIA gene was higher in HPV16（＋） than that in HPV16（-） （P〈0.05）. Conclusion： The RASSFIA gene change is a relatively late event in cervical carcinomas. The detection of LOH and MSI of RASSFIA gene might be helpful to the early diagnosis and the screening of cervical carcinoma. It might also be useful for predicting the prognosis of cervical carcinoma.     

Genetic alterrations of microsatellite markers at chromosome 17 in non-small cell lung cancer

Despite the high incidence and mortality, the exact molecular mechanism of the tumorigenesis and progression of lung cancer is still unclear. Alterations in oncogenes and onco-supressor genes have been described in lung cancer. Recent studies have started to define microsatellite instability (MI) and loss of heterozygosity (LOH) in genetic material of patients with lung cancer.[1] Microsatellite instability represents mutations of the short-tandem repeat sequences distributed within the geno…     

Loss of heterozygosity occurs at the D11S29 locus on chromosome 11q23 in invasive cervical carcinoma.

Allelotypic detection of loss of heterozygosity (LOH) has been used to identify putative tumour-suppressor genes. Loci on human chromosome 11q23 are frequently altered in malignant disease, and LOH has been reported at an anonymous D11S29 locus at 11q23 in a proportion of breast and ovarian cancers and malignant melanomas. Previous studies have reported a high frequency of LOH in cervical carcinoma mapping to 11q23. Using polymerase chain reaction techniques employing probes for a recently described polymorphic dinucleotide microsatellite within this locus, we have searched for LOH in 69 cases of invasive cervical carcinoma. Genomic material was microdissected from sections cut from archival paraffin-embedded material, using the patients'' constitutional genotype as a control Sixty-two (90%) of the cases were informative, and LOH occurred in 25/62 (40%) of tumours. Loss of an arm or single chromosome 11 is a well-recognised event in cervical carcinoma, and by employing other microsatellite polymorphisms mapping to 11q13 and 11p11-p12 we excluded those cases with widespread allelic loss. By doing so, LOH at D11S29 was found in 16/53 (30%) of tumours. The findings suggest a putative tumour-suppressor gene on 11q involved in cervical carcinogenesis.     

Frequent FHIT gene loss of heterozygosity in human papillomavirus-infected non-smoking female lung cancer in Taiwan

The fragile histidine triad (FHIT), located in chromosome region 3p14.2, had been reported to be a frequent allele with loss of heterozygosity (LOH) in smoking lung cancer and HPV-associated cervical cancer. Additionally, FHIT LOH may act as a tumor suppressor gene to involve in smoking-related lung tumorigenesis and HPV-related cervical tumorigenesis, respectively. In our previous report, a high prevalence of HPV 16/18 infection has been observed in non-smoking female lung cancer patients, and thus it was speculated that HPV 16/18 infection may increase the LOH frequency of FHIT in female cases to implicate in lung tumorigenesis. In this study, 157 lung cancer patients were enrolled and subjected to FHIT LOH analysis with three microsatellite markers. As expected, the frequency of FHIT LOH in males, smokers, and squamous cell carcinomas lung cancer patients was significantly higher than that of their corresponding counterpart (P=0.020 for gender, P<0.001 for smoking status, and P=0.038 for tumor type). Interestingly, a correlation between HPV 16 infection and FHIT LOH was observed in female lung cancer cases. To be more specifically, FHIT LOH frequency was remarkably increased from 18% (6 of 33) in HPV 16 non-infected female cases to 46% (11 of 24) in HPV 16 infected cases. The higher frequency of FHIT LOH observed in HPV 16-infected female lung tumors suggested that the involvement of HPV infection in lung tumorigenesis may, at least in part, be mediated through FHIT LOH.     

Localization of a tumour-suppressor gene associated with human oral cancer on 7q31.1

To search for the existence of a tumour-suppressor gene (TSG) associated with oral squamous cell carcinoma (SCC), PCR analysis of microsatellite polymorphisms corresponding to 14 loci which map to chromosome 7q21.3-qter was performed to screen 35 patients with oral SCC for loss of heterozygosity (LOH). LOH was observed in at least one of the loci in 19 of 34 (55.9%) informative cases. Among the loci tested, frequent LOH was restricted at D7S522 on chromosome 7q31.1, which was measured within 1 cM. Furthermore, we detected microsatellite instability (MI) in 11 of 35 (31.4%) cases tested. Our observations indicate that alterations of chromosome 7q are associated with oral SCC tumorigenesis and that 7q31.1 might harbour at least one putative TSG. Int. J. Cancer 75:671–674, 1998.© 1998 Wiley-Liss, Inc.     

The clinical value of microsatellite instability and a loss in heterozygosity in sporadic breast cancers

We analyzed loss of heterozygosity (LOH) and microsatellite instability (MI) in 108 cases of sporadic breast cancers using 22 microsatellite markers on 12 chromosomes. LOH was frequently seen in 1p (13%), 6p (18%), 8p (11%), 11p (18%), 13q (21%), 16q (31%), 17p (44%) and 17q (29%). Individual patients were scored according to the degree of LOH at the above eight chromosomal markers. Patients with no LOH were scored as 1, patients with one to three LOH were scored as 2, and patients with four or more LOH were scored as 3. A high LOH score correlated with a high histological grade (p = 0.019) and a poor prognosis (p = 0.0035). Eleven (10.2%) of 108 patients with breast cancer showed MI, with 6 cases showing MI at a single locus and 5 at multiple loci. Of the 11 Mi-positive patients only one had lymph node involvement (p = 0.015), none had histological grade 3 disease, and Mi-positive patients tended to have a better prognosis than Mi-negative ones. These data suggest that MI may be an early event in mammary tumorigenesis, and that LOH occurs at a later stage. The LOH score may be a useful prognostic marker of operable breast cancer.     

Allelic loss and prognosis in carcinoma of the uterine cervix

Cervical carcinomas develop as a result of multiple genetic alterations. As the genetic alterations are the cause of malignant transformation, it is likely that specific genetic alterations lead to specific clinical behaviour. The aim of this study was (i) to localise chromosome arms that harbour likely tumour-suppressor genes, by analysing loss of heterozygosity (LOH) and (ii) to study the association of LOH with clinicopathological parameters. To define the regions of interest, we studied the presence of loss of heterozygosity at all chromosomes in 67 cervical carcinomas (stages IB and IIA) with 81 polymorphic markers. In addition, all frequent allelic imbalances were correlated with HPV status and clinicopathologic parameters including survival, FIGO-stage, lymph-node metastasis, tumour size, number of mitoses, vaso-invasion and histologic type. LOH at a frequency over 25% was observed at sites on 9 chromosome arms: 3p21, 4p16.1-15, 6p, 6q22.3-23.1, 11q22-24, 15q11-21.1, 17p13.3, 18q22-qter and Xq. LOH of chromosome 6q14-16.2, 6p22 and 17p13 correlated marginally with HPV-16 positivity. LOH on chromosome 3p21 was weakly correlated with high mitotic activity, while LOH on chromosomes 11q23.3, 15q21.1 and 17p13 correlated with low mitotic activity. LOH at chromosome 17p13 associated marginally with FIGO stage I, while LOH at chromosome 15q associated weakly with FIGO stage II. When chromosome 18q showed LOH in the tumour, the patients had decreased survival (p = 0.024). We conclude that, in carcinoma of the uterine cervix, a novel tumour-suppressor gene may be present on chromosome 15q21 and that patients with LOH on chromosome 18q have relatively poor survival (p = 0.025). Int. J. Cancer (Pred. Oncol.) 79:411–417, 1998. © 1998 Wiley-Liss, Inc.     

Analysis of Genetic Alterations Related to the Development and Progression of Breast Carcinoma

To study genetic alterations related to the development and/or progression of breast carcinoma, we examined amplification of the ERBB2, INT2, and MYC genes, as well as loss of heterozygosity (LOH) at loci on 11p, 16q, 17p ( D17S5 and TP53 ), 17q ( D17S74 and NME1 ), and 18q by restriction fragment length polymorphism analysis. The subjects were 26 patients with small breast carcinomas (≦2 cm) and 88 patients with larger breast carcinomas (2 to < 5 cm). All patients were free of distant metastasis. As tumor diameter increased, the frequency of oncogene amplification and LOH at all loci except D17S5 increased. However, there was no relationship between tumor diameter and amplification of specific oncogenes or allelic loss at specific loci. LOH at D17S5 was detected in 40% of small breast carcinomas (≦2 cm) and 43% of larger breast carcinomas (2 to < 5 cm). There was a significant correlation of LOH at D17S5 with INT2 amplification or with LOH on 11p, 16q, and 18q. These findings suggest that LOH at D17S5 may be involved in the early stage of breast carcinoma development, while INT2 amplification and LOH at 11p, 16q, and 18q appear to be genetic alterations that occur with tumor progression. In addition, as lymph node metastases were significantly related to amplification of the ERBB2 and MYC genes, and LOH of the NME1 gene, these genetic alterations may play a role in the mechanism of lymph node metastases.     

Different pattern of loss of heterozygosity among endocervical-type adenocarcinoma, endometrioid-type adenocarcinoma and adenoma malignum of the uterine cervix

It is unclear which chromosome arms frequently show loss of heterozygosity (LOH) in adenocarcinoma of the uterine cervix. To identify such chromosomal arms, LOH on 52 different chromosome loci was examined using laser capture microdissection and PCR-LOH analysis in 25 common-type adenocarcinomas, comprising 13 cases of endocervical type, 12 cases of endometrioid type and 7 cases of adenoma malignum without the component of conventional endocervical-type adenocarcinoma (designated as "pure" form). In adenocarcinomas of endocervical type and endometrioid type, LOH was commonly detected on chromosome arms 17p (62% and 50%, respectively), 1p (33% and 67%) and 22q (40% and 33%). In addition, endocervical-type adenocarcinoma frequently (> or = 30%) showed LOH on 18p (71%), 19q (50%), 19p (38%) and 16q (38%), whereas endometrioid-type adenocarcinoma frequently showed LOH on 10q (43%) and 5q (40%). LOH was only sporadically detected on 9q, 18q, or 21q in 3 of 7 cases of "pure" adenoma malignum. In a case of coexistence of "pure" adenoma malignum and adenocarcinoma in situ (AIS), LOH on 1q, 5p, 11p, 17p, 18p and 18q was detected only in AIS. LOH was accumulated on a number of chromosome arms in the adenocarcinoma at the early developmental stage before stromal invasion. Chromosomal arms that are prone to show LOH appeared to differ between the 2 types of cervical adenocarcinoma. We could suggest that "pure" adenoma malignum is of clonal and neoplastic nature in view of the detection of LOH.     

Genetic aberration on chromosome 10 in human oral squamous cell carcinoma

Recently a tumor suppressor gene, a deleted in malignant brain tumor gene (DMBT1), was detected on chromosome 10. In some types of tumors, the frequent deletion of DMBT1 locus have been reported as well as loss of heterozygosity (LOH) on chromosome 10. However, little is known relating to human oral squamous cell carcinoma (OSCC). To study the genetic aberrations on chromosome 10 in OSCC, we performed polymerase chain reaction (PCR) analysis of microsatellite polymorphisms corresponding to 16 loci, containing 2 DMBT1 loci. We examined 38 oral primary squamous cell carcinoma (SCC) tissues and corresponding normal tissues. Microsatellite instability (MI) was detected at least on 1 of the 16 loci in 15 (39.5%) of 38 cases, and loss of heterozygosity (LOH) at least 1 of the 16 loci was also observed in 28 (73.7%) of 38 cases. LOH was accumulated at D10S202 (34.6%) and D10S217 (28.6%), suggesting the presence of two putative tumor suppressor genes associated with OSCC. The 2 DMBT1 loci, D10S209 and D10S587, had comparatively high frequent LOH (20.0 and 22.7%, respectively), maybe indicating the important role of DMBT1 in OSCC. No significant correlation between histological differentiation and LOH was found. These results suggest that genetic aberrations on chromosome 10 play important roles in the oncogenesis of OSCC.