Mutation analysis of the Smad6 and Smad7 gene in human ovarian cancers

The Smad6 and Smad7 genes are members of the Smad family, involved in the transforming growth factor-beta (TGF-beta) signaling pathway. Mutations in TGF-beta receptors and their cytoplasmic elements of transduction signals commonly accompany various cancers. Using PCR-SSCP analysis we searched for the presence of Smad6 and Smad7 gene mutations in 30 human ovarian cancers and 4 ovarian cancer cell lines, and found that 12 cases (35.3%) had a polymorphism in intron 2 of the Smad6 gene and that 8 cases (23.5%) had a polymorphism at codon 208 in the Smad7 gene. Because these polymorphisms were not accompanied by amino acid substitution, the present results show that the mutations in the Smad6 and Smad7 genes are unlikely to be involved in human ovarian cancers.

Modifying effects of ethinylestradiol but not methoxychlor on N-ethyl-N-nitrosourea-induced uterine carcinogenesis in heterozygous p53-deficient CBA mice

It is unknown whether endocrine-disrupting chemicals (EDCs) with estrogenic activities have any modifying effects on uterine carcinogenesis. In our previous study, we established a uterine-carcinogenesis model that is useful for detecting tumor-modifying effects of EDCs by the administration of N-ethyl-N-nitrosourea (ENU) to female heterozygous p53-deficient CBA mice [p53 (+/-) mice]. To investigate the effects of ethinylestradiol (EE) and methoxychlor (MXC) on development of ENU-induced uterine tumors, female p53 (+/-) mice and their wild-type littermates [p53 (+/+) mice] received an intraperitoneal injection of 120 mg/kg body weight (bw) of ENU, followed, in Group 1, by no further treatment; in Group 2, by a diet containing 1 ppm EE; in Group 3, by a diet containing 5 ppm EE for 4 weeks and 2.5 ppm EE thereafter; and in Group 4, by a diet containing 2000 ppm MXC for 26 weeks. Uterine proliferative lesions that were induced were composed of both endometrial-stromal and epithelial-cell types. Endometrial stromal sarcomas were induced in p53 (+/-) mice of Groups 1 to 4, and the incidence (87%) in Group 3 was significantly increased compared to Group 1 (47%). Atypical hyperplasias (clear-cell type) of the endometrial gland in p53 (+/-) mice were seen at incidences of 0, 14, 60, and 0% in Groups 1, 2, 3, and 4, respectively, while their incidence in p53 (+/+) mice was 0, 7, 53, and 0%, respectively, with a significant difference between Groups 1 and 3 in both cases. One p53 (+/-) mouse in Group 3 also had an adenocarcinoma consisting of clear cells, and the PCNA labeling indices of the clear-cell atypical hyperplasias, and this endometrial adenocarcinoma, were higher than those of glandular hyperplasias. The present study suggests that 2.5 ppm EE, but not MXC, exerts tumor-promoting effects on stromal and epithelial proliferative lesions of the uteri in p53 (+/-) mice initiated with ENU.

[The effect of FHIT gene on renal cell carcinomas]

OBJECTIVE

To study the potential role of FHIT gene in renal cell carcinomas.

METHODS

Cancerous tissues derived from 23 patients with renal cell carcinomas and an established cell line were examined for the alteration of FHIT gene transcripts and structure of genomic DNA by using RT-PCR and Southern blot hybridization assays.

RESULTS

Eight point three percent(2/24) of cancerous tissues exhibited aberrant transcripts. The transcript in the renal-cell cancer cell line appeared a small-size one when cDNA was amplified with outside nest primer; absent expression of transcript was shown when amplified with inside nest primer. About twenty percent(5/24) cancerous tissues showed genomic rearrangement in FHIT gene locus.

CONCLUSION

FHIT gene exhibited aberrant transcripts and genomics in some of renal cell cancers. Therefore change of FHIT gene may play a role in development of renal cell carcinomas.

Clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres: a novel member of the perivascular epithelioid clear cell family of tumors with a predilection for children and young adults

The perivascular epithelioid cell family of tumors (PEComas), defined by their co-expression of melanocytic and muscle markers, includes angiomyolipoma, lymphangioleiomyoma, and clear cell "sugar" tumors of the lung, pancreas, and uterus. We present seven cases of a unique and previously unrecognized tumor of children and young adults, which represents a new addition to the PEComa group of tumors. Culled from three institutions over a 50-year period, all cases occurred in or immediately adjacent to the ligamentum teres and falciform ligament. Six patients were female and one male; their ages ranged from 3 to 21 years (median, 11 yrs). Tumor sizes ranged from 5 to 20 cm (median, 8 cm). All cases consisted of clear to faintly eosinophilic spindled cells arranged in fascicular and nested patterns. The cells had small but distinct nucleoli and low mitotic activity. Immunohistochemically, all cases were positive with antibodies to gp100 protein (HMB-45) and negative for S-100 protein. In three of the seven cases studied immunohistochemically, the tumors expressed smooth muscle actin, melan-A, microphthalmia transcription factor (MiTF), and myosin, but not desmin. No expression of the TSC2 gene product, tuberin, was seen in three cases. One case studied cytogenetically disclosed a t(3;10). Follow-up data, available in six of seven cases (median duration, 18 mos), showed five patients to be free of disease and one to have a radiographically presumed lung metastasis. We think these tumors comprise a new entity for which we propose the term "clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres." The differential diagnosis of these tumors includes clear cell sarcoma of tendons and aponeuroses, leiomyosarcoma, and angiomyolipoma.

Nuclear DNA content-derived parameters correlated with heterogeneous expression of p53 and bcl-2 proteins in clear cell renal carcinomas

BACKGROUND

p53 and bcl-2 are two key genes involved in cell cycle and cell death regulation. Altered expression or mutation of these genes has been found in human cancers and also has been identified in clear cell renal carcinoma (RCC). Their role in RCC progression, however, is still unclear. By contrast, the prognostic significance of ploidy and S-phase fraction (SPF) have been studied extensively in RCC. To better characterize the biologic role of p53 and bcl-2 oncoproteins in RCC, we offer a multisample correlative analysis of the expression of these two proteins with ploidy and SPF.

METHODS

Ploidy and SPF along with p53 and bcl-2 expression were analyzed in 296 specimens, selected by multiple sampling of 33 consecutive operable RCCs. The expression of p53 and bcl-2 proteins was studied by immunohistochemistry, and SPF and tumor ploidy were studied by flow cytometry.

RESULTS

In our study, 4 of 32 (12.5%) were found to be diploid, and 28 of 32 (87.5%) cases showed an abnormal DNA content. Among the aneuploid tumors, 14 of 28 (50%) were multiploid. Heterogeneous DNA content was detected in 21 of 32 (65.6%) tumors and was correlated with the more advanced Robson stage tumor (P = 0. 03). Intratumor heterogeneity also was detected for p53 and bcl-2 protein expression. Expression of p53 protein correlated with the lack of bcl-2 protein expression (P = 0.0032), aneuploidy (P < 0. 0001), and high SPF (P = 0.0006), whereas bcl-2 expression was associated with a normal DNA content (P < 0.0001) and low SPF (P = 0. 035).

CONCLUSIONS

Within each RCC, p53 and bcl-2 expression is markedly heterogeneous. Our results depicted a scenario in which bcl-2 protein, expressed by normal renal parenchyma, is still present in euploid cell clones of RCC but disappears during the progression of renal neoplasm toward a more aggressive phenotype characterized by overexpression of p53 protein, aneuploidy, and high SPF.

Novel mutations of the von hippel-lindau tumor-suppressor gene and rare DNA hypermethylation in renal-cell carcinoma cell lines of the clear-cell type

Renal-cell carcinoma (RCC) is the most common neoplasm of the kidney, accounting for about 3% of all adult malignancies. Histopathologically, 80% of all cases can be classified as clear-cell RCC. Of these, approximately 55% to 70% are associated with mutations in the von Hippel-Lindau (VHL) tumor-suppressor gene. Here, new mutations of the VHL gene were defined by the use of temperature gradient gel electrophoresis and subsequent sequencing. In addition, DNA hypermethylation, an alternative mechanism of VHL gene silencing, was evaluated by methylation-specific PCR. Twenty-six clear-cell, 3 chromophilic, and 2 chromophobic RCC cell lines were analyzed. Among the clear-cell RCC cell lines tested, 12 (47%) contained 13 mutations overall: 8 (62%) in exon 1, 3 (23%) in exon 2, and 2 (15%) in exon 3. Ten of these mutations have thus far not been described. All single base pair changes were transversions. Six mutations led to alteration of a single amino acid. Seven mutations generated a frameshift or a stop codon. One cell line contained a complex duplication of 36 bp. All cell lines with mutations showed loss of heterozygosity in the VHL gene. No mutations could be detected in the chromophilic or chromophobic RCC samples. Significant hypermethylation was not observed in any of the cell lines. These data provide further evidence that distinct mutations in the VHL gene are a characteristic feature of clear-cell RCC. In contrast, hypermethylation of the gene is probably a rare event. The high frequency of transversion mutations suggests a role for exogenous carcinogens in the etiology of clear-cell RCCs.

Alterations of the DNA repair gene OGG1 in human clear cell carcinomas of the kidney

The OGG1 gene, which codes for a DNA repair protein with antimutator activity, is located on chromosome 3p25, a frequent site of allelic deletions in many types of human tumors, including renal clear cell cancers. We present the analysis of 99 renal tumors for alterations in the OGG1 gene to determine its association with tumorigenesis. Loss of heterozygosity in the 3p25 region was found for 85% of the informative cases. We detected somatic missense mutations of the OGG1 gene in 4 of the 99 tumor samples. Biochemical analysis of the mutant proteins revealed that a substitution at codon 46 impairs the enzymatic activity. We also describe the occurrence of several polymorphisms as well as aberrantly spliced OGG1 transcripts.

[An approach to early genetic alterations in precancerous cells]

To investigate the potential role of the PTEN tumor-suppressor gene in the carcinogenesis of ovarian endometrioid carcinoma and its related subtype, clear cell carcinoma, we examined 20 ovarian endometrioid carcinomas, 24 clear cell carcinomas and 34 solitary endometrial cysts of the ovary for LOH at 10q23.3 and point mutations of the PTEN gene, using a laser-assisted microdissection method. LOH was found in 8 of 19 ovarian endometrioid carcinomas (42.1%), 6 of 22 clear cell carcinomas (27.3%) and 13 of 23 solitary endometrial cysts (56.5%). Somatic mutations in the PTEN gene were identified in 4 of 20 ovarian endometrioid carcinomas (20.0%), 2 of 24 clear cell carcinomas (8.3%) and 7 of 34 solitary endometrial cysts (20.6%). In 5 endometrioid carcinomas with endometriosis, 3 displayed LOH events common to both the carcinoma and the endometriosis. In 7 clear cell carcinomas with endometriosis, 3 displayed LOH events common to both the carcinoma and the endometriosis. In no cases there were LOH events in the endometriosis only. These results indicate that inactivation of the PTEN gene is an early event in the development of both endometrioid and clear cell carcinoma of the ovary. A laser-assisted microdissection method enables us to collect target cells without contamination by non-tumor cells. We expect that this technique will be very useful for investigating genetic alterations in cancerous or precancerous lesions. Early genetic alterations in various precancerous cells detected by light microscopy can be readily identified by the tissue-microdissection method.

Expression of thyroid hormone receptors is disturbed in human renal clear cell carcinoma

Human renal clear cell carcinoma (RCCC) accounts for up to 2% of human cancers. To find out if thyroid hormone (T3) and its receptors (TRs) play a role in tumorigenesis of RCCC, the expression of TRs was evaluated on mRNA and protein level. It was found that TRalpha (both alpha1 and alpha2) mRNA amount was significantly decreased in tumors while compared with healthy kidney tissue, and this decrease was deepest in G1 (well differentiated) RCCCs. In contrast, TRalpha1 protein was 1.6x overexpressed in tumors. TRbeta1 mRNA amount was overexpressed in 30% and significantly decreased in 70% of examined tumors. On the protein level, TRbeta1 amount was 1.7x lower in tumors than in healthy controls.

Detection of human papillomavirus types 16 and 18 in human neoplastic endometrium: lack of correlation with established prognostic factors

HPV (types 16 and 18) DNA sequences are present in the majority of precancerous and cancerous lesions of the human uterine cervix. However, data concerning the involvement of HPVs infection in the pathogenesis of endometrial cancer are controversial. In the current study we investigated the frequency of the HPV types 16 and 18, detected by PCR amplification using the type 16- and 18-specific primers within the E7 Open Reading Frame (ORF) sequence, in 54 human endometrial carcinomas obtained from women of Polish origin. Moreover, we assessed the possible association of the HPV with the clinicopathological features of the cancer, patients' outcome as well as with the K-ras codon 12 gene point mutations. HPV type 16 was present in eleven out of 54 (20%) endometrial tumors, while HPV type 18 was detected only in three out of 54 (4%) neoplasms analyzed. HPV infection was not related either to the patients' age (r=0.11; p=0.428, Spearman correlation test) or to the clinicopathological parameters and patients' prognosis. A higher incidence of HPV 16/18 was detected in well (G1) differentiated than in moderately (G2) and poorly (G3) differentiated endometrial adenocarcinomas, but the difference was not statistically significant. Moreover, none of HPV-positive endometrial carcinomas harbored K-ras codon 12 gene point mutations. Our results suggest that some of the endometrial carcinomas are associated with HPV infection but the presence of the human papillamovirus types 16/18 is not related to the clinicopathological or prognostical features of the neoplasm.

Genetic aberrations detected by comparative genomic hybridization in ovarian clear cell adenocarcinomas

Genetic abnormalities were detected by comparative genomic hybridization (CGH) in 12 ovarian clear cell adenocarcinomas. DNA sequence copy number abnormalities (CNAs) occurring in more than 20% of the cancers included increased copy numbers of 8q11-q13, 8q21-q22, 8q23, 8q24-qter, 17q25-qter, 20q13-qter and 21q22-qter and reduced copy numbers of 19p. Increases in copy numbers of 8q11-q13, 8q21-q22, 8q23 and 8q24-qter occurred more frequently in disease-free patients than in recurrent/non-surviving patients (p < 0.05). However, increases in copy numbers of 17q25-qter and 20q13-qter occurred more frequently in recurrent/non-surviving patients than in disease-free patients (p < 0.05). Furthermore, increases in copy numbers of 17q25-qter and 20q13-qter occurred together (p < 0.05). Additionally, there were negative correlations between increases in copy numbers of 8q21-q22 and 17q25-qter, and between 8q21-q22 and 20q13-qter (p < 0.05). It appears that ovarian clear cell adenocarcinomas can be classified into two subtypes, one being cancer with an increase in copy numbers of 8q and the other being cancer with increases in copy numbers of 17q25-qter and 20q13-qter.

Anticorresponding mutations of the KRAS and PTEN genes in human endometrial cancer

PTEN is a newly isolated candidate tumor suppressor gene and its mutation is the most frequently found in endometrial cancer (EC), a very common female pelvic malignant disease. Mutations of the KRAS gene are also reported in this disease. Recent analysis of the PTEN protein suggested the possibility that this protein acts in the same pathway as does the RAS protein. To elucidate this possibility further, we performed a mutation analysis of these two genes in 44 endometrial cancer specimens (38 primary tumors and 6 cell lines). Altogether 23 (52%) of 44 tumors had mutations in either PTEN or KRAS, but none of them had mutations in both of these genes. These results support the idea that the protein products of these two genes act in the same growth regulatory pathway in the endometrium.

Clear cell carcinoma of the fimbria of the fallopian tube in a BRCA1 carrier undergoing prophylactic surgery

We report the case history of a patient with a family history of breast and ovarian cancer who was subsequently found to be a carrier of the BRCA1 gene, in whom a tiny focus of clear cell carcinoma was found at the fimbrial end of one fallopian tube when she underwent prophylactic hysterectomy and bilateral salpingoophorectomy. The implications of this finding are discussed.

Loss of heterozygosity on chromosome 17q in epithelial ovarian tumors: association with carcinomas with serous differentiation

Loss of heterozygosity (LOH) on chromosome 17q is frequent in epithelial ovarian tumors, but its clinicopathologic significance remains to be elucidated. DNA of 50 patients with epithelial ovarian tumors was extracted from blood and from fresh-frozen and paraffin-embedded tissue (14 benign, 7 borderline, and 29 malignant). Six microsatellite loci were amplified by PCR (D17S250, TRHA1, D17S800, D17S855, D17S579, D17S513). LOH was scored by the absence or reduction of the signal to less than 50% of one of the alleles in tumor DNA compared with normal DNA. LOH was identified on chromosome 17q in at least one locus in 12 tumors (24%), all of them carcinomas (12 of 29 tumors, 41.3%). It occurred more frequently among high-grade serous carcinomas (8 of 14 tumors, 57%) and mixed endometrioid-serous carcinomas (2 of 5, 40%). LOH was detected in all informative markers of 10 tumors, suggesting the complete loss of an entire chromosome 17 homologue. Patients with LOH-positive carcinomas were older than those with LOH-negative malignant tumors (mean ages 67 and 49). The results support the hypothesis that LOH on chromosome 17q may be associated with the development of ovarian cancers in elderly patients, particularly with high-grade serous or mixed endometrioid-serous carcinomas.

Immunohistochemical detection of the Wilms' tumor gene (WT1) in epithelial ovarian tumors

The Wilms' tumor gene WT1 plays multiple roles in the development of the genitourinary organs and Wilms' tumors. The aims of this study were to immunohistochemically evaluate WT1 expression in normal female genital tissues and in epithelial ovarian tumors and to look for correlations between WT1 expression and histologic subtypes and cell proliferation in epithelial ovarian tumors. In normal female genital organs, WT1 expression was recognized in ovarian surface epithelium, the lining of inclusion cysts, and tubal epithelium, but not in the cervical or endometrial epithelium. In epithelial ovarian tumors, serous tumors generally revealed a high WT1 expression. Among adenocarcinomas, serous carcinoma revealed a significantly higher WT1 expression than the other histologic subtypes. There were no significant correlations between the WT1 labeling index and the Ki-67 labeling index, and no significant difference in survival between those showing high and low WT1 expression among the malignant cases. These results suggest that WT1 expression may be related to cell differentiation, and that the histologic subtypes of epithelial ovarian carcinomas may differ considerably in their biological characteristics.

Trisomy of chromosome 10 in two cases of ovarian carcinoma

Simple numerical chromosome aberrations have been observed in tumorigenesis and may point to indicative initiating or early events in tumorigenesis. We have identified two cases of ovarian carcinomas with trisomy of chromosome 10 using conventional GTG-banding and fluorescence in situ hybridization. This is, to our knowledge, the first report of trisomy 10 as a simple karyotypic abnormality observed in ovarian carcinoma. These results suggest that further studies investigating whether chromosome 10 genes are associated with the pathogenesis of some ovarian tumors are warranted.

PTEN mutations in endometrial carcinomas: a molecular and clinicopathologic analysis of 38 cases

PTEN mutations have been reported to be frequent in endometrioid carinomas of the endometrium (EEC). Some correlation has been found between PTEN mutations and the presence of microsatellite instability (MI) in EEC, but no convincing cause-effect relationship for such association has been offered. DNA of 38 patients with endometrial carcinoma (EC) was extracted from blood and from fresh-frozen and paraffin-embedded tumor tissue. PTEN mutations were detected by single-strand conformation polymorphism (SSCP) analysis and DNA sequencing. Results were correlated with MI status and clinicopathologic data. PTEN mutations were detected in 17 tumors (44.7%), and they were more frequent in endometrioid (EEC) (17 of 33, 51.5%) than in nonendometrioid carcinomas (NEEC) (0 of 5, 0%). PTEN mutational spectrum differed between MI+ and MItumors. PTEN mutations were detected in 9 of 15 MI+ tumors (60%), but in only 8 of 23 MI- neoplasms (34.8%). In EC with MI, PTEN mutations were detected in short coding mononucleotide repeats (A)s and (A)6 in 4 of 9 carcinomas (44.4%). These results confirm that PTEN is an important target gene in endometrial carcinogenesis. The occurrence of PTEN mutations in short coding mononucleotide repeats in MI-positive tumors suggests that these mutations may be secondary to deficiencies in mismatch repair and gives some explanation for the frequent presence of PTEN mutations in these tumors.

Differentiation of primary and metastatic clear cell tumors in the liver by in situ hybridization for albumin messenger RNA

Clear cell neoplasms presenting as metastatic hepatic masses may be difficult to differentiate histologically and immunohistochemically from hepatocellular carcinoma (HCC) with prominent clear cell features, especially in small biopsy specimens. In situ hybridization (ISH) for albumin messenger RNA (mRNA) has been previously shown to be sensitive and specific for the detection of hepatocellular differentiation, but its use for the identification of clear cell HCC has not been previously evaluated. Among 309 cases of hepatocellular carcinoma diagnosed at Mayo Clinic between 1985 and 1998, 30 cases (9.7%) with at least 30% (range, 30%-90%; median 60%) clear cells were studied by ISH for albumin mRNA. In addition, immunohistochemical expression of AFP and polyclonal CEA, serum determination of AFP, and histopathologic analyses of the tumor were done. Forty-two clear cell tumors were used as a control group: 21 metastatic clear cell tumors to the liver (14 renal cell carcinomas and 7 adrenal cortical carcinomas) and 21 primary clear cell tumors of the retroperitoneum (10 renal cell carcinomas, 5 adrenal cortical adenomas, 4 adrenal cortical carcinomas, and 2 ovarian carcinomas). ISH for albumin mRNA was reactive in 28 of 30 cases of clear cell HCC (93%). Clear cell HCC expressed AFP (15 cases; 50%) and polyclonal CEA (19 cases; 63%). Tumors expressed either AFP or polyclonal CEA in 23 cases (77%). Elevated serum AFP was present in 24 of 26 cases (92%). These results indicate that ISH for albumin mRNA is a useful method to distinguish clear cell HCC from other clear cell carcinomas metastatic to the liver and clear cell neoplasms in the retroperitoneum.

Loss of heterozygosity in P53, BRCA1, and estrogen receptor genes and correlation to expression of p53 protein in ovarian epithelial tumors of different cell types and biological behavior

Loss of heterozygosity (LOH) of tumor suppressor genes (TSGs) in ovarian epithelial tumors of differing cell types and biological behavior has not been thoroughly investigated. Moreover, there have been conflicting reports correlating LOH of the p53 gene to overexpression of p53 protein. This study evaluated 34 formalin-fixed, paraffin-embedded ovarian epithelial tumors for LOH by polymerase chain reaction (PCR) for the following microsatellite markers: TP53(17p13.1/p53 gene), D17S579(17q/BRCA1 gene), and ESR (6q24-27/estrogen receptor gene). LOH of the TP53 marker was detected in 4 (44%) of 9 informative serous cystadenocarcinomas (SCa) but in 0 of 4 informative clear cell carcinomas (CCa) and 0 of 5 informative serous tumors of low malignant potential (SLMP). LOH of the BRCA1 marker was detected in 5 (83%) of 6 informative SCa, but in 1 (13%) of 8 informative CCa and 1 (14%) of 7 informative SLMP. LOH of the ESR marker was detected in 4 (50%) of 8 informative SCa, but in 0 of 4 informative CCa and 1 (16%) of 6 informative SLMP. p53 protein overexpression was present in 8 of 12 SCa but did not correlate to TP53 LOH. LOH for TP53, D17S579/ BRCA1, and ESR is common in ovarian SCa, and is observed in primary tumors as well as metastases. In contrast, these genetic alterations are less common in CCa and in the biologically less aggressive SLMP tumors. These data suggest different mechanisms of oncogenesis in ovarian epithelial tumors of different cell types and biological behavior.

A case-control study of galactose consumption and metabolism in relation to ovarian cancer

Consumption or metabolism of dairy sugar and ovarian cancer have been linked based on evidence that galactose may be toxic to ovarian germ cells and that ovarian cancer is induced in animals by depletion of oocytes. We assessed consumption of dairy products and obtained blood for biochemical and molecular genetic assessment of galactose metabolism in 563 women with newly diagnosed epithelial ovarian cancer and 523 control women selected either by random digit dialing or through lists of residents in eastern Massachusetts and New Hampshire. We observed no significant differences between cases and controls in usual consumption of various types of dairy products or total daily lactose (the principal source of galactose in the diet); nor did we find that RBC activity of either galactose-1-phosphate uridyl transferase (GALT) or galactokinase differed. The mean (and SE) activity of uridine diphospho-galactose 4'-epimerase (in micromoles per hour per gram of hemoglobin) was, however, significantly lower (P < 0.005) in cases compared with controls, 20.32 (0.31) versus 21.64 (0.36). Ovarian cancer cases were also more likely to carry the N314D polymorphism of the GALT gene, generally predisposing to lower GALT activity. The difference was most evident for endometrioid and clear cell types of ovarian cancer, in which 3.9% of cases were found to be homozygous for N314D compared with 0.4% of controls, yielding an odds ratio and 95% confidence interval of 14.17 (2.62-76.60). We conclude that, whereas adult consumption of lactose carries no clear risk for the disease, certain genetic or biochemical features of galactose metabolism may influence disease risk for particular types of ovarian cancer.

Four new human renal cell carcinoma cell lines expressing globo-series gangliosides

Clinicopathological studies revealed that monosialosyl galactosyl globoside (MSGG) and disialosyl galactosyl globoside (DSGG) expressed by renal cell carcinoma (RCC) are one of the biochemical indicator related to the metastatic potential. The present study examines the characteristics of four new human RCC cell lines and compares the expression of MSGG and DSGG among them using TLC immunostaining and flow cytometry. TOS-1 and TOS-2 were derived from metastatic subcutaneous tissues. TOS-3 and TOS-3LN were derived from the primary lesion and from metastatic lymph nodes respectively. Monolayer culture, light microscopy and electron microscopy of these cells showed that these cell lines were derived from RCC. TLC immunostaining and flow cytometric analysis revealed increased levels of MSGG in TOS-2 and TOS-3LN, and increased DSGG in TOS-1 and TOS-3LN. These cell lines would be useful for functional studies of globo-series ganglioside expressed by RCC.

Establishment and characterization of human ovarian clear cell adenocarcinoma cell line (SMOV-2), and its cytotoxity by anticancer agents

A novel cell line derived from a surgically resected ovarian clear cell adenocarcinoma of 46 year-old Japanese woman was established and designated SMOV-2. Cells of this lineage were continuously propagated in vitro over 44 months and were grown in a mono-layered sheet with a doubling time of 48.2 hours. The histopathology of the transplanted tumor in nude mice showed two distinctive cell types, hobnail cells and clear cells, which demonstrated recognizable characteristics of clear cell adenocarcinoma, as compared to resected original tumors. At the molecular level, SMOV-2 cells had the wild type p53 genes that were free from missence mutations. Anticancer agents (cisplatin and paclitaxel) were examined for cytotoxity against these SMOV-2 cells in vitro. These examinations revealed that the chemotherapy-treated cells had decreased proliferation, cell cycle arrests, and induction of apoptosis by the anticancer agents. As can be gleaned from this research, SMOV-2 is a valuable model to study the mechanism of apoptotic responses of solid tumors to future anticancer agents.