Genetic alterations distinguish different types of ovarian tumors

Seventy-four sporadic ovarian tumors were studied for loss of heterozygosity (LOH) and microsatellite instability (MI) with 20 polymorphic markers on chromosome 17 and at least I marker on every other chromosome. Additionally, activation of the K-ras oncogene was examined through mutation analysis of codon 12. A majority of the tumors analyzed were low grade and/or of the mucinous histologic type. A negative correlation between LOH on chromosome 17 and K-ras activation was observed, with the former alteration present in the majority of high grade serous and endometrioid tumors and the latter most commonly found in the mucinous and low malignant potential (LMP) tumors. In 60% of cases where LOH on chromosome 17 was present, it was observed at all informative markers, indicating chromosome loss. In these cases, frequent events of LOH were observed on the other chromosomes. When confined events of LOH were observed on chromosome 17, fewer events of LOH were observed on the other chromosomes. In the absence of LOH on chromosome 17, LOH on other chromosomes was rare. K-ras activation was most commonly observed in tumors with no LOH events. Two endometrioid tumors and 2 mucinous tumors demonstrated MI. Our data support the involvement of different molecular pathways in the development of different types of ovarian tumors. © 1995 Wiley-Liss, Inc.     

Allelic loss at 19q12 and Xq11-12 predict an adverse clinical outcome in patients with mucinous ovarian tumours of low malignant potential

Ovarian tumours of low malignant potential (LMP) are intermediate between adenomas and ovarian carcinomas. These tumours are often associated with a significantly better prognosis than ovarian carcinomas. However, a subset of these tumours can progress and become lethal. In order to seek sensitive diagnostic tools for monitoring patients after surgical operation, we performed a genome-wide scan for loss of heterozygosity (LOH) in 41 mucinous LMPs using 91 polymorphic microsatellite markers at an average interval of 50 cM across all of the human chromosomes and 25 LOH markers reportedly associated with ovarian carcinoma. In addition, we assessed whether clinicopathological parameters, microvessel density, Ki-67 labeling index, apoptotic index or p53 overexpression would be useful for predicting the postoperative outcome of LMP patients. Of the 116 markers examined, 19q12 and Xq11-12 showed significant correlation between postoperative progression-free survival time and LOH status (P<0.05). Patients with a high Ki-67 labeling index had a significantly poorer progression-free survival time than those with lower levels (P=0.042). Other clinicopathological factors and immunohistochemical analysis had no correlation with progression-free survival time in this series of patients. When the combination of LOH at 19q12 and/or Xq11-12 was assessed using Cox's regression analysis, patients with tumours that showed LOH at these positions were at greatest risk of progression (P=0.0073). These findings suggest that the identification of LOH at 19q12 and/or Xq11-12 in former mucinous LMP sites should alert the clinician to the presence of a potentially aggressive lesion in the coelomic epithelium, even if a distinction between second primary tumours or recurrence could not be determined.     

Genetic analysis of benign ovarian tumors

Ovarian cancer represents a major cause of cancer death among women and yet remarkably little is known about its etiology. The paradigm established by the colorectal carcinogenesis model would suggest that ovarian cancers are likely to arise through malignant transformation of benign ovarian tumors. However, molecular genetic data that could answer this important question is lacking. In our study, we analyzed 80 benign ovarian tumors for TP53 and K-ras mutations and for LOH on chromosomes 6, 7, 9, 11 and 17 using 56 microsatellite markers. Twenty-five percent (5/20) of non-epithelial tumors and 73% (44/60) of epithelial tumors exhibited LOH on at least 1 chromosome arm. A particularly high frequency of LOH was detected among the epithelial tumors on chromosome arms 6q (17%), 7p (17%), 7q (27%) and 11p (18%), which are also regions of frequent LOH among ovarian carcinomas. No K-ras mutations were detected in any tumor but somatic TP53 mutations were detected in 2/34 (6%) serous and 1/26 (4%) mucinous epithelial tumors. In contrast to most previous studies our data is derived from a relatively large number of microdissected tumors and is likely to represent a more accurate picture of the frequency of alterations in these tumors. We conclude that LOH is common in benign ovarian tumors, suggesting that inactivation of tumor suppressor genes are pivotal in their development. The high frequency of alterations is consistent with their being precursors to malignant disease but does not unequivocally prove this continuum. It does however provide a framework for future analysis of the molecular genetic etiology of ovarian tumorigenesis.     

Distribution of microsatellite instability in Danish ovarian tumor patients and the prognostic value in ovarian cancer patients

The repeated frequency of microsatellite instability (MSI) in ovarian cancer (OC) ranges from 0% to 50%. Most MSI studies including OC patients have involved relatively small number of tumors, a wide range of different MSI markers, different patient characteristics, and varying criteria for defining tumors as MSI positive. Thus, no conclusive evidence about MSI occurrence in OC has been provided and the large variation has made interpretation of these previous studies difficult. The majority of MSI studies have been performed on OC cases with few borderline ovarian tumor (BOT) cases included. Few BOT studies showed no evidence of MSI, but in one study the frequency of MSI was 27.7% with all tumors of serous type, suggesting that MSI may play a role in the development of serous BOT. The aim of our study was to determine the frequency of MSI using a panel of 16 dinucleotide markers: TP53, D17S250, CACNLB1, D18S58, D19S49, DXS538, DXS454, D5S117, D5S107, D6S284, D6S305, D9S171, D9S15, D11S554, D11S29, and D13S272 in tissue from patients with OC or BOT and to correlate the presence of MSI at these markers with the clinical information, such as FIGO stage, histological type, age, and survival in OC. The overall frequencies of MSI were within 2-10%. We observed MSI at different loci and with different extent (2.3-9.8%) in the different histopathological types. In both BOT and OC cases, we observed that all high MSI (MSI-H) were of serous type. No significant difference in disease specific survival was found between stage III/IV OC patients who presented MSI compared to patients being microsatellite stable (MSS) (p = 0.72). In conclusion, we found no association to any of the clinical parameters evaluated, although a tendency of a higher frequency of MSI was observed among serous OC.     

Expression profiling of serous low malignant potential, low-grade, and high-grade tumors of the ovary

Papillary serous low malignant potential (LMP) tumors are characterized by malignant features and metastatic potential yet display a benign clinical course. The role of LMP tumors in the development of invasive epithelial cancer of the ovary is not clearly defined. The aim of this study is to determine the relationships among LMP tumors and invasive ovarian cancers and identify genes contributing to their phenotypes. Affymetrix U133 Plus 2.0 microarrays (Santa Clara, CA) were used to interrogate 80 microdissected serous LMP tumors and invasive ovarian malignancies along with 10 ovarian surface epithelium (OSE) brushings. Gene expression profiles for each tumor class were used to complete unsupervised hierarchical clustering analyses and identify differentially expressed genes contributing to these associations. Unsupervised hierarchical clustering analysis revealed a distinct separation between clusters containing borderline and high-grade lesions. The majority of low-grade tumors clustered with LMP tumors. Comparing OSE with high-grade and LMP expression profiles revealed enhanced expression of genes linked to cell proliferation, chromosomal instability, and epigenetic silencing in high-grade cancers, whereas LMP tumors displayed activated p53 signaling. The expression profiles of LMP, low-grade, and high-grade papillary serous ovarian carcinomas suggest that LMP tumors are distinct from high-grade cancers; however, they are remarkably similar to low-grade cancers. Prominent expression of p53 pathway members may play an important role in the LMP tumor phenotype.     

Loss of heterozygosity on chromosome 13q12-q14, BRCA-2 mutations and lack of BRCA-2 promoter hypermethylation in sporadic epithelial ovarian tumors

BACKGROUND: BRCA-1 and BRCA-2 are tumor suppressor genes in familial breast-ovarian carcinoma syndrome. BRCA-1 is also a tumor suppressor gene in sporadic ovarian carcinomas. However, the role of BRCA-2 in sporadic ovarian tumors remains unclear. METHODS: DNA from 52 patients with clinically apparent sporadic ovarian tumors was extracted from blood and from fresh-frozen tumor tissue and normal tissue (10 benign, 7 borderline, and 35 malignant). Loss of heterozygosity (LOH) was analyzed in six microsatellite loci on chromosome 13q. BRCA-2 mutations were detected by single-strand conformation polymorphism analysis and the protein truncation test. BRCA-2 promoter methylation was evaluated by methylation specific polymerase chain reaction analysis. RESULTS: LOH on chromosome 13q12-q14 was identified in 16 tumors (30.8%): Fifteen of these tumors were carcinomas (15 of 35 tumors; 42.8%) and one was a borderline tumor. LOH was frequent in carcinomas with serous differentiation (12 of 16 tumors; 75%). LOH on chromosome 13q12-q14 coexisted with LOH on chromosome 17q in 10 carcinomas. BRCA-2 methylation was not detected in any tumor. BRCA-2 mutations were found in three tumors (one somatic nonsense and two germline frameshift). BRCA-2 fulfilled the two hits for a tumor suppressor gene in these three tumors; in one of them, a BRCA-1 tumor suppressor role had been demonstrated previously. CONCLUSIONS: The results suggest that BRCA-1 and BRCA-2 may act synergically in sporadic ovarian carcinomas with serous differentiation. The demonstration of BRCA-2 germline mutations in patients with ovarian carcinoma with LOH on chromosome 13q12-q14 and lack of a remarkable family history of cancer suggest that the proportion of ovarian carcinomas that result from hereditary predisposition may be higher than previously estimated.     

Prognostic value of estrogen receptor and progesterone receptor tumor expression in Danish ovarian cancer patients: from the 'MALOVA' ovarian cancer study

Estrogen and progesterone are important hormones secreted by the ovary acting through specific receptors. Tumor tissue expression profiles of these have demonstrated prognostic value in malignancies such as breast, uterine and prostate cancer. In this study, including tissue samples from 773 Danish patients with an ovarian tumor, we evaluated whether estrogen receptor (ER) and progesterone receptor (PR) expression correlated with clinico-pathological parameters, and a possible prognostic impact on ovarian cancer (OC) patients was investigated. Using tissue array and immunohistochemistry, we analyzed the ER and PR expression levels in tissues from 582 women with OC and 191 women with low malignancy potential (LMP) ovarian tumors. Our results demonstrated that ER was expressed in 30 of the 191 LMP tumors (16%) and in 207 of the 582 OC (36%). PR was expressed in 38 LMP tumors (20%) and in 115 OC (20%). For both tumor types an excess of positive tumors was found in the serous compared to the mucinous subtype (p< or =0.00001). The frequency of ER expression-positive OC increased with increasing FIGO stage (p=0.0003), and the frequency of PR-positive tumors increased with increasing histological grade (p=0.0006). In a Cox survival analysis, a tissue ER and PR expression 10% or higher was found to imply an independent significant advantageous course of patient disease-specific survival (ER: hazard ratio (HR), 0.80; 95% confidence interval (CI), 0.63-0.99; PR: HR, 0.69; 95% CI, 0.51-0.94) together with FIGO stage, residual tumor after primary surgery, age at diagnosis and other histological types vs. serous adenocarcinoma. The histological grade of tumor was found to have no independent prognostic value. The prognostic value of ER and PR was found additive with a HR for patients with high ER and PR expression of 0.48 (95% CI, 0.31-0.74) compared to patients with <10% expression for both receptors. In conclusion, our results predict that an elevated expression of ER and PR, alone and in combination, point to a favorable outcome for patients with OC.     

Survival among women with borderline ovarian tumors and ovarian carcinoma: a population-based analysis

BACKGROUND: Serous and mucinous ovarian tumors of low malignant potential (LMP-S and LMP-M, respectively) are noninvasive tumors that portend excellent survival when confined to the ovary. Comparison of the survival for women with LMP tumors staged as distant with women who have carcinoma may have important implications for diagnostic terminology and clinical management. METHODS: The authors compared relative survival rates among patients diagnosed with ovarian tumors during the period 1988-1999 (with follow-up through 2000) by histologic type, disease stage, tumor grade (for carcinomas), and patient age, using data from the Surveillance, Epidemiology, and End Results Program. RESULTS: The overall relative survival rate at 10 years (+/- 1.96 standard errors) was 96.9% +/- 2.3% for women with LMP-S tumors, 30.4% +/- 1.7% for women with serous carcinoma (CA-S); 94.0% +/- 3.1% for women with LMP-M tumors, and 64.7% +/- 3.4% for women with mucinous carcinoma (CA-M). The survival rate at 10 years for women with distant-stage LMP-S tumors was 89.9% +/- 5.3%, compared with 96.1% +/- 8.6% for women with well differentiated, localized CA-S. The survival rate for women with distant-stage LMP-M tumors at 5 years was 85.5% +/- 9.0%, compared with 95.5% +/- 3.4% for women with well differentiated, localized CA-M (data for 10 years were limited). Mucinous ovarian neoplasms were associated with an excess of second malignancies of the digestive tract. CONCLUSIONS: Relative survival among women with distant-stage LMP tumors was not 100% and resembled the survival of women who had carcinoma exhibiting favorable prognostic features (localized stage). Future studies of women with high-stage LMP tumors are required to clarify the pathogenesis of extraovarian lesions and their implications for management and prognosis.     

Ovarian tumors of low malignant potential

Opinion statement Ovarian tumors of low malignant potential (LMP) differ from epithelial ovarian carcinoma in etiology, molecular biology, and prognosis. LMP tumors are not precursor lesions to ovarian carcinoma. Treatment is primarily surgical. Women found to have an ovarian tumor of LMP should undergo removal of the involved adnexa; surgical staging; and cytoreductive surgery. Women in the reproductive years should be given the option of conservative surgery, preserving the contralateral adnexa and uterus. There is no proven benefit to adjuvant chemotherapy or radiotherapy after primary surgery. In most cases, the diagnosis of an ovarian tumor of LMP conveys good prognosis, with excellent long-term survival.     

Genetic classification of ovarian carcinoma based on microsatellite analysis: relationship to clinicopathological features and patient survival

Ovarian carcinomas can progress through two pathways of genomic instability: chromosomal instability (CIN) and microsatellite instability (MSI). However, it is unknown whether these two mechanisms could be distinguished from each other in the molecular characteristics in ovarian carcinomas. We hypothesized that these two pathways are not always independent in ovarian carcinomas. We classified 51 ovarian carcinomas based on their MSI and CIN status using microsatellite analysis and assessed whether these carcinogenic pathways affect the clinicopathological features and patient survival. Of the 51 cases, 77.4% of the tumors were microsatellite stable (MSS), 5.9% were MSI-Low (MSI-L) whilst, 16.7% were MSI-High (MSI-H). Overall, 56.8% of the tumors had at least one loss of heterozygosity (LOH) event, i.e., 56.8% CIN. Notably, we identified a significant degree of overlap between the MSI and CIN pathways. Of the 34 tumors with LOH events (CIN), 5 (14.7%) were MSI-H. In addition, of the 7 tumors that were MSI-H, 5 (71.4%) had one or more LOH events (CIN). We also identified a group of 29.4% of all tumors that did not demonstrate any evidence of either of the two pathways of genomic instability as they were MSS/MSI-L with no evidence of LOH events (CIN negative). Furthermore, patients with CIN with MSS/MSI-L have a significantly shorter overall survival compared to those in other genetic categories (P=0.019). Cox regression analysis revealed that tumors with CIN with MSS/MSI-L exhibit a poor prognostic outcome after adjustment for FIGO stage and grade. These findings suggest that some ovarian carcinomas have a significant degree of overlap between the two pathways of genomic instability and that the genetic classification using microsatellite markers may represent a potential new biomarker of risk prediction in ovarian carcinoma.     

TFF3 Expression as Stratification Marker in Borderline Epithelial Tumors of the Ovary

Borderline tumors (BOT) of the ovary account for 10% to 20% of ovarian neoplasms. Like ovarian cancer, BOT encompass several different histological subtypes (serous, mucinous, endometrioid, clear cell, transitional cell and mixed) with serous (SBOT) and mucinous (MBOT) the most common. Current hypotheses suggest low-grade serous carcinoma may develop in a stepwise fashion from SBOT whereas the majority of high grade serous carcinomas develop rapidly presumably from inclusion cysts or ovarian surface epithelium. The pathogenesis of mucinous ovarian tumors is still puzzling. Molecular markers could help to better define relationships between such entities. Trefoil factor-3 (TFF3) is an estrogen-regulated gene associated with prognosis in different types of cancer. It has also been included in a recent marker panel predicting subtypes of ovarian carcinoma. We analyzed the expression of TFF3 by immunohistochemistry in a cohort of 137 BOT and its association with histopathological features. Overall expression rate of TFF3 was 21.9%. None of the BOT with serous and endometrioid histology displayed strong TFF3 expression. On the other hand, TFF3 was highly expressed in 61.4% of MBOT cases and 33.3% of BOT with mixed histology (P < 0.001) suggesting a potential function of the protein in that subtypes. Associations of TFF3 expression with FIGO stage and micropapillary pattern were significant in the overall cohort but confounded by their correlation with histological subtypes. The highly specific expression of TFF3 in MBOT may help to further clarify potential relationships of tumors with mucinous histology and warrants further studies.     

Allelic loss on chromosome 1 is associated with tumor progression of cervical carcinoma.

BACKGROUND: Alterations in chromosome 1 are common in human malignancies. The frequency of loss of heterozygosity (LOH) on chromosome 1 in cervical carcinoma and its clinical significance are not clearly understood. METHODS: LOH on chromosome 1 was studied in 100 cervical carcinomas by the polymerase chain reaction (PCR) using 29 highly polymorphic microsatellite markers spaced approximately 10 centimorgans apart. Loci with high frequencies of LOH were identified and the findings were correlated with clinicopathologic characteristics. RESULTS: LOH on chromosome 1 at 1 or more loci was detected in 93% of tumors. The frequencies of LOH at locus D1S2829 (1p31), D1S2663 (1p36.3), and D1S2725 (1q25) exceeded 30%, and 12 other loci exhibited frequencies of LOH of 20-30%. Advanced stage tumors had a significantly higher percentage of informative microsatellite markers with LOH than early stage tumors. Of the 29 microsatellite markers studied, 4 loci had a significantly higher frequency of LOH in Stage III and IV tumors than in earlier stage tumors. CONCLUSIONS: Frequent aberrations on chromosome 1 in cervical carcinoma suggest that inactivation of tumor suppressor genes is important in cervical tumorigenesis. Higher frequencies of LOH in Stage III and IV tumors suggest that chromosome 1 changes are late events in cervical carcinoma. The findings of this study are consistent with earlier reports that suggest that tumor suppressor genes are present at 1p36.3 and 1p31. To the authors' knowledge, the high frequency of LOH mapped to 1q25 has not been reported previously. Its significance awaits further clarification.     

Whole-genome allelotyping identified distinct loss-of-heterozygosity patterns in mucinous ovarian and appendiceal carcinomas.

PURPOSE: Mucinous adenocarcinoma of the ovary is one of the common histologic types of ovarian cancer. Its pathogenesis is largely unknown. In addition, the differential diagnosis of metastatic mucinous carcinomas to the ovaries, particularly those originating from the appendix, remains challenging. The purpose of this study is to identify molecular biomarkers for mucinous ovarian adenocarcinoma and compare them with those of appendiceal origin. EXPERIMENTAL DESIGN: Genome-wide loss-of-heterozygosity (LOH) analysis was done on DNA isolated from 28 microdissected primary mucinous ovarian carcinomas and five appendiceal adenocarcinomas. Markers from high-loss regions were selected for further analysis on a total of 32 ovarian and 14 appendiceal cancers. RESULTS: High levels of LOH rates (>40%) were detected on chromosome arms 9p, 17p, and 21q in mucinous ovarian carcinoma cases. The frequency of allelic loss was similar between high-grade and low-grade mucinous ovarian carcinoma cases but was significantly higher in ovarian versus appendiceal cases. In addition, LOH rates on five chromosomal loci were statistically different between ovarian and appendiceal carcinomas. CONCLUSION: A high frequency of LOH can be found in mucinous ovarian adenocarcinomas independent of grade. Despite histologic similarities between mucinous ovarian carcinomas and metastatic appendiceal carcinomas, they have distinct LOH profiles, which may be used for distinguishing the two diseases.     

Molecular profiling of sporadic colorectal tumors by microsatellite analysis

To investigate the prognostic value of multiple genetic alterations, individual molecular tumor profiles were established in 79 sporadic colorectal carcinomas (41 stage II and 38 stage III). Tumors were analyzed for allelic loss (LOH) and genetic instability (MSI) using 14 microsatellites intragenic to or associated with tumor suppressor or DNA mismatch repair genes. Molecular profiling identified tumors with LOH at multiple loci without microsatellite instability (MSS), tumors with high levels of LOH and low level microsatellite marker instability (MSI-L), and tumors with high levels of MSI (MSI-H), but rare LOH. K-ras mutations occurred more frequently in MSS/MSI-L carcinomas (26%) than in MSI-H colorectal tumors (10%), the latter showing a high frequency of TGFbeta type II frameshift mutations (82%). Correlation of molecular and clinical data revealed a better prognosis for stage III tumor patients displaying 5q12 loss rather than retention of heterozygosity. Thus, molecular profiling allows the identification of new prognostic markers and might facilitate the stratification of colorectal cancer patients.     

蛋白酪氨酸激酶PTK7在卵巢浆液性肿瘤中的表达及意义

背景与目的：新近发现的蛋白酪氨酸激酶-7(protein tyrosine kinase-7,PTK7)基因与多种肿瘤的发生、发展和浸润有关。本研究旨在探讨PTK7在卵巢浆液性肿瘤中的表达及其与临床分期、组织学分级、转移和预后等指标的关系,分析PTK7表达在卵巢浆液性肿瘤中的诊断及预后价值。方法：制备3株卵巢癌细胞系(HO8910、SKOV3、A2780)爬片,并收集14例正常输卵管上皮组织,6例良性浆液性卵巢肿瘤,51例交界性浆液性卵巢肿瘤和97例卵巢浆液性癌组织蜡块,采用免疫组化EliVision两步法检测PTK7蛋白的表达,结合相关病理指标,采用χ²检验、Fisher确切概率法、Kaplan-Meier法进行统计分析。结果：PTK7在卵巢癌细胞株HO8910及A2780中呈阴性表达,在SKOV3中成弱阳性表达。PTK7在92.86%(13/14)的正常输卵管上皮、83.33%(5/6)的良性浆液性卵巢肿瘤、45.10%(23/51)的交界性浆液性卵巢肿瘤和28.87%(28/97)的浆液性卵巢癌中阳性表达。正常输卵管上皮与良性浆液性肿瘤、良性浆液性肿瘤与交界性浆液性肿瘤之间PTK7表达差异无统计学意义(P=0.521,P=0.102)。浆液性卵巢癌与正常输卵管上皮、良性浆液性肿瘤以及交界性浆液性肿瘤之间PTK7表达差异有统计学意义(P=0.000,P=0.012,P=0.048)。PTK7在交界性浆液性卵巢肿瘤中的表达与其临床分期、淋巴结和(或)腹膜转移情况有关(P=0.038,P=0.038),与其发生部位、年龄无关(P=0.088,P=0.896)。PTK7在卵巢浆液癌中的表达与其临床分期、WHO分级、MDACC病理分级有关(P=0.011,P=0.004,P=0.000),与其发生部位、转移情况、肿瘤直径、年龄无关(P=0.326,P=0.524,P=0.588,P=0.584)。卵巢浆液癌中PTK7阳性组的生存率显著高于阴性组(P=0.017)。结论：PTK7在输卵管正常上皮、良性浆液性卵巢肿瘤、交界性浆液性卵巢肿瘤和浆液性癌中表达呈逐步下调趋势。PTK7表达与卵巢上皮性浆液性肿瘤的较晚临床分期、高组织分级、预后差呈正相关,可能成为卵巢浆液性肿瘤辅助诊断及临床预后的新指标。     

Loss of heterozygosity and microsatellite instability in epithelial hyperplasia of the breast

We evaluated loss of heterozygosity (LOH) and microsatellite instability (MSI) in epithelial hyperplasia of the breast by the PCR method using microsatellite markers. Seven loci of 16q, 17p, 17q, and 18q were examined in 35 lesions of epithelial hyperplasia observed in non-neoplastic breast tissue of eight breast carcinoma cases, and 29 lesions were observed within 19 fibroadenomas. These hyperplastic lesions were classified by standard criteria into three groups, namely, mild, moderate and atypical ductal hyperplasia (ADH). In the breast carcinoma cases, the frequency of loss of heterozygosity was 40% in mild, 50% in moderate, and 100% in ADH; while in the fibroadenoma cases, the frequency was 10% in mild, 27% in moderate, and 25% in ADH; total frequency of LOH was statistically higher in carcinoma cases than in fibroadenoma cases. On the other hand, the frequency of microsatellite instability was higher in fibroadenoma cases (28%) than in breast carcinoma cases (11%). Furthermore, we analyzed two cases of noninvasive ductal carcinoma arising in fibroadenoma, which had various types of hyperplasia along with carcinoma in situ, and many hyperplasias showed LOH at several of the same markers as carcinoma in situ. From those results, we speculated that LOH at these markers is an early event in mammary tumorigenesis, and some of the hyperplastic lesions with LOH have precancerous natures.     

Mucinous cancers have fewer genomic alterations than more common classes of breast cancer

Mucinous cancers of the breast are distinguished histologically by their abundant pools of mucin and low degree of nuclear pleomorphism. Relative to the more common breast cancers of no distinctive type (ductal carcinoma), mucinous cancers have a relatively favorable prognosis. In a study of chromosomal changes in mucinous cancers, we evaluated the extent of loss of heterozygosity (LOH) at chromosomal regions commonly deleted in usual infiltrating ductal carcinoma, including markers on chromosomal arms 1p, 1q, 3p, 6q, 8p, 9p, 11p, 11q, 13q, 16q, 17p, and 17q. Remarkably, we found an average frequency of LOH of only 1.9 of these 12 chromosomal arms in 18 cases of mucinous carcinoma, compared to an average frequency of LOH of 6.4 of these same chromosomal arms in cases of infiltrating ductal cancer. In three of the 18 cases of mucinous carcinoma studied, including one case with regional lymph node metastases, no LOH was seen at any of the 12 chromosomal regions studied. We considered the possibility of other chromosomal loci being more commonly affected in mucinous cancers and conducted comparative genomic hybridization on six of the cases. These studies demonstrated a low overall frequency of genomic copy number changes (mean of 3.1 changes per case) and failed to reveal any other chromosomal locus with frequent losses that had not been evaluated by microsatellite analysis. Together, these data indicate that mucinous cancers of the breast do not have the extensive genomic alterations that are typically found in more common variants of breast cancer. Thus, mucinous cancers most likely have less genetic instability than most other forms of breast cancer and the molecular pathogenesis of this form of breast cancer is likely to be substantially different than that of usual ductal breast cancer.     

A survey of epithelial inclusions in the ovarian cortex of 470 patients.

The ovaries of 470 patients obtained for various indications at operation revealed 178 with 193 ovarian cysts and tumors - including 63 serous, 23 endometrial, and 27 mucinous - as well as 103 with tubal (serous), 35 with endometrial, and 2 with cervical (mucinous) epithelial inclusions. A very high frequency of transformation of mucinous epithelial inclusions into cysts and tumors contrasted with about 40% similar transformation of serous and endometrial inclusions into cysts and tumors.     

Borderline ovarian tumors

Borderline ovarian tumors account for approximately 15% of all epithelial ovarian tumors. In the early 1970s, borderline tumors were categorized as either serous or mucinous with overall survival rates of 75–90%. Since then, it has been recognized that the two categories are heterogonous. There are now many different groups following the recognition of serous tumors with microinvasion, non‐invasive and invasive peritoneal implants and a micropapillary pattern, and of mucinous tumors with microinvasion, intraepithelial carcinoma and pseudomyxoma peritoneal implants, in addition to further delineation of endometrial, clear cell and transitional cell tumors with atypical proliferation. This review outlines the most recent information regarding the epidemiology, pathology and clinical management of borderline tumors. Surgical management to excise all visible tumors remains the cornerstone of therapy. Because borderline ovarian tumors often occur in reproductive‐age women, fertility is an important issue. Conservative surgery is a safe in carefully selected patients. Effective non‐surgical therapies are yet to be identified.     

Identification of novel variant, 1484delG in the 3'UTR of H3F3B, a member of the histone 3B replacement family, in ovarian tumors

Previous studies have implicated the chromosomal region at 17q25 as harboring tumor suppressor genes based on the frequent loss of heterozygosity (LOH) observed in epithelial ovarian cancers (EOC). RT-PCR validation of Affymetrix GeneChip expression of H3F3B, a member of the 3B histone family that maps to 17q25.1, revealed a doublet band in cDNA from one of four EOC cell lines, OV90. In contrast to three other EOC cell lines (TOV81D, TOV112D and TOV21G) and primary cultures derived from normal ovarian surface epithelial cells (NOSE), sequence analysis of the cDNA revealed a deletion of G at position 1484 of the transcribed sequence which is located within the 3'UTR of H3F3B. OV90 was derived from ascites fluid of an undifferentiated adenocarcinoma of ovarian origin. The variant allele was identified in 1 of 65 (2%) healthy women with no prior history of cancer and in 5 participants with ovarian tumors comprising of 4 of 79 (5%) malignant EOC, none of 10 low malignancy potential tumors, and 1 of 8 (13%) benign tumors. All carriers of the variant alleles were heterozygous and tumor samples did not exhibit preferential LOH of the normal allele. The variant allele was identified in EOC samples of clear cell (1 of 20), mucinous (1 of 8), mixed cell (1 of 3) and undifferentiated (1 of 2) histopathological subtypes but none of 34 serous or 12 endometrioid subtype tumors. One of 3 mucinous benign tumors also harbored the variant allele. The functional significance of the variant is unknown, however its presence in rare subtypes of ovarian epithelial tumors warrants further investigation.