Allelic loss at chromosome 13q12-q13 is associated with poor prognosis in familial and sporadic breast cancer.

Loss of heterozygosity (LOH) was analysed in 84 primary tumours from sporadic, familial and hereditary breast cancer using five microsatellite markers spanning the chromosomal region 13q12-q13 which harbours the BRCA2 breast cancer susceptibility gene, and using one other marker located within the RBI tumour-suppressor gene at 13q14. LOH at the BRCA2 region was found in 34% and at RBI in 27% of the tumours. Selective LOH at BRCA2 occurred in 7% of the tumours, whereas selective LOH at RBI was observed in another 7%. Moreover, a few tumours demonstrated a restricted deletion pattern, suggesting the presence of additional tumour-suppressor genes both proximal and distal of BRCA2. LOH at BRCA2 was significantly correlated to high S-phase values, low oestrogen and progesterone receptor content and DNA non-diploidy. LOH at BRCA2 was also associated, albeit non-significantly, with large tumour size and the ductal and medullar histological types. No correlation was found with lymph node status, patient age or a family history of breast cancer. A highly significant and independent correlation existed between LOH at BRCA2 and early recurrence and death. LOH at RBI was not associated with the above mentioned factors or prognosis. The present study does not provide conclusive evidence that BRCA2 is the sole target for deletions at 13q12-q13 in breast tumours. However, the results suggest that inactivation of one or several tumour-suppressor genes in the 13q12-q13 region confer a strong tumour growth potential and poor prognosis in both familial and sporadic breast cancer.     

Loss of heterozygosity in sporadic breast tumours at the BRCA2 locus on chromosome 13q12-q13.

Loss of heterozygosity (LOH) on chromosome 13 occurs on 25-30% of breast tumours. This may reflect the inactivation of the retinoblastoma susceptibility gene RB1. However, recently another candidate tumour-suppressor gene has been identified on chromosome 13 by linkage analysis, the breast cancer susceptibility gene BRCA2. To investigate the involvement of BRCA2 in sporadic breast cancer 200 breast tumours were tested for LOH on chromosome band 13q12-q14, using 11 highly polymorphic microsatellite markers. LOH was found in 65 tumours, which all showed simultaneously loss of BRCA2 and RB1. Of 12 breast tumour cell lines tested with polymorphic microsatellite markers, seven showed a contiguous region of homozygosity on 13q12-q14, suggesting LOH in the tumour from which the cell line had been derived. One cell line showed homozygosity in the BRCA2 region and heterozygosity at RB1. This is the only indication that BRCA2 is a distinct target for LOH on chromosome 13 in addition to RB1.     

Frequent loss of heterozygosity on chromosome 17 at 17q11.2-q12 in Barrett's adenocarcinoma.

Allelic loss on chromosome 17 in 18 Barrett''s oesophageal tumours was analysed with 17 polymorphic microsatellite markers. Loss of heterozygosity (LOH) of one or more markers was seen in 72% (13 of 18) tumours on 17p and 56% (10 of 18) on 17q. The highest 17p losses were found at D17S799 (62%, five of eight) and D17S261 (55%, five of nine), while loss at the p53 locus was 31% (5 of 16). The highest loss on 17q was found at the TCF-2 (17q11.2-q12) locus with 66% (8 of 12) LOH. TCF-2 was the only marker lost in two of the tumour samples; furthermore, TCF-2 was lost in four other tumours which retained heterozygosity at the markers on either side of it, D17S261 and D17S740. Six markers were used to assess LOH at 17q11.2-q12, and five of eight of the tumour specimens which had LOH at TCF-2 had no other loss on 17q. No statistically significant correlations were found between loss on 17q or 17p and any clinicopathological parameters. We propose from these data that the 17q11.2-q12 region contains a novel predisposing gene in Barrett''s adenocarcinomas and may represent the site of a tumour-suppressor gene.     

Allelic imbalance at 11q23-q24 chromosome associated with estrogen and radiation-induced breast cancer progression

Multiple genetic alterations are common in cancers including those of the breast. The mechanisms leading to these alterations such as point mutations, gene amplifications, deletions and replication error are often associated with frequent and consistent loss of heterozygosity (LOH) or microsatellite instability (MSI). Several cytological and molecular studies have shown high frequency loss of genetic information on the long arm of chromosome 11 (i.e., 11q) in various primary breast cancers. In the present study allelic alterations in a refined position on the long arm of chromosome 11 were studied to identify the spectrum of induced damage at different stages of malignant transformation of MCF-10F cell lines after exposure to high-LET radiation using alpha-particles and exposure to estradiol by using PCR-single strand conformation polymorphism (SSCP) and fluorescence in situ hybridization (FISH) analysis. Microsatellite markers were selected from chromosome 11 (11q23-q24 loci) and it was found that frequency of allelic imbalance occurs at different stages of tumor progression with a range of 15-45% depending on the marker studied. These results strongly suggested the presence of several tumor suppressor genes in this critical region of chromosome 11 (11q23-q24). It also represents the first indication of allele loss at these loci in human breast epithelial cells induced by radiation and estrogen treatment suggesting a potential interventional target in breast carcinogenesis.     

Loss of heterozygosity on chromosome 6q14-q24 is associated with poor outcome in children and adolescents with T-cell lymphoblastic lymphoma.

Deletions of chromosome 6q have been reported in several hematological malignancies, but data are not conclusive regarding their biological and prognostic impact. Therefore, we focused on pediatric patients diagnosed with T-cell lymphoblastic lymphoma (T-LBL) treated uniformly according to the NHL-BFM95 protocol. We used loss-of-heterozygosity (LOH) analysis of 25 microsatellite markers located on chromosome 6q14-q24. Fragment-length analysis was performed on ABI-PRISM3100 Genetic-Analyzer. Eligibility criterion was > or =3 informative markers. Between April 1995 and March 2003, 185 T-LBL patients were treated according to the NHL-BFM95 protocol. Five-year event-free (EFS) and disease-free survival (DFS) were 79+/-3 and 87+/-3% (median follow-up 4.7 [1.2-10.1] years). Sixty-one patients were evaluable for LOH analysis, including 18 out of 23 patients with relapse. EFS and DFS were 67+/-6 and 69+/-6% for these 61 patients. Testing of 853 markers in the 61 patients identified the presence of LOH in 19 patients (31%): 13 of the 18 relapse patients and five of the 41 in complete remission (odds ratio 18.7, 95% confidence interval 4.7-75.3). One LOH-positive patient died from treatment-related toxicity. We conclude that LOH on chromosome 6q14-q24 may have conferred a high risk of relapse on our group of children with T-LBL treated according to the NHL-BFM95 protocol.     

Three independently deleted regions at chromosome arm 16q in human prostate cancer: allelic loss at 16q24.1-q24.2 is associated with aggressive behaviour of the disease, recurrent growth, poor differentiation of the tumour and poor prognosis for the patient.

Loss of heterozygosity at chromosome arm 16q is a frequent event in human prostate cancer. In this study, loss of heterozygosity at 16q was studied in 44 prostate cancer patients exhibiting various clinical features. Fifteen polymorphic polymerase chain reaction (PCR) markers were used to identify the separately deleted areas and the findings were compared with clinicopathological variables and 5-year survival of the patients. The results indicated that there are at least three independently deleted regions at 16q. Allelic losses at the central and distal areas were associated significantly with aggressive behaviour of the disease (16q24.1-q24.2, P < 0.01, and 16q24.3-qter, P < 0.05), and the central area of deletion was further significantly associated with poorly differentiated tumour cells (P < 0.05) and with recurrent (P < 0.01) growth of the tumour. During the follow-up period, 28% of the patients initially with M0 disease developed distant metastases. Of the patients showing allelic loss at 16q24.1-q24.2, distant metastasis were found in 45% during the 5-year follow-up period, and 31% of the patients showing loss at 16q21.1 also developed distant metastases. After the 5-year follow-up period, 14 (32%) of the patients remained alive, whereas 19 (43%) had died because of their prostate cancer. The overall survival rate of the patients showing allelic loss at 16q21.1 or 16q24.1-q24.2 was significantly lower than that of the patients with retained heterozygosity.     

Loss of heterozygosity at 10q in tumors of the upper respiratory tract is associated with poor prognosis.

Frequent loss of a specific chromosomic region in cancers is often associated with inactivation of a tumor-suppressor gene. The long arm of chromosome 10 is deleted in several types of tumor, among them squamous-cell carcinomas of the head and neck (HNSCC). To determine the role of 10q deletions in the tumorigenesis of the upper respiratory tract, 47 HNSCCs were examined for loss of heterozygosity (LOH) at 10q: 43% of the cases analyzed showed LOH at 10q, and 2 distinct hot spots of deletion were identified, at 10q22-23 and 10q25-26. The possible involvement of pTEN/MMAC1, a tumor-suppressor gene mapped at 10q23, was also evaluated. No mutation, homozygous deletion or loss of expression of pTEN/MMAC1 was detected, indicating that inactivation of this gene plays a minor role in HNSCC development. Interestingly, the frequency of deletion at 10q was greater in invasive carcinoma than in adjacent carcinoma in situ, and a significant association between LOH and poor prognosis was observed. Taken together, our results suggest the presence in the long arm of chromosome 10 of (a) tumor-suppressor gene(s) other than pTEN/MMAC1 and presumably involved in the malignant progression of tumors of the upper respiratory tract. Int. J. Cancer (Pred. Oncol.) 84:432-436, 1999.     

鼻咽癌染色体11q13等位基因杂合性缺失的研究

目的：对鼻咽癌中染色体11q13上的4个位点进行微卫星多态性分析,明确这些位点染色体位基因杂合性丢失的情况。方法：采用显微切割的方法获取较纯的肿瘤组织,然后用PCR的方法以PYGM、D11S4946、D11S449和INT－2为引物,对38例鼻咽癌进行微卫生序列分析。结果38例鼻咽癌组织中,至少有一个位点出现杂合性缺失者36例,占94．7％。其中D11S4946杂合性缺失的频率最高,占78．8％（26／33）,其余的引物分别为：INT－2占51．5％（17／33）,PYGM占45．5％（15／33）,D11S449占45．7％（16／35）。结论鼻咽癌染色体11q13区发生高频率杂合性缺失,提示缺失区域可能存在与鼻咽癌发生有关的抑癌基因。     

Lymph node metastasis is associated with allelic loss on chromosome 13q12-13 in esophageal squamous cell carcinoma.

Allelotype analysis of whole chromosomes showed that loss of heterozygosity (LOH) on 13q was exclusively associated with lymph node metastasis and poor prognosis in esophageal squamous cell carcinoma (ESC). To identify a locus responsible for lymph node metastasis, we performed fine deletion mapping on 13q by analyzing 60 ESCs with 18 polymorphic markers. Allelic loss was observed with at least one marker in 34 tumors (56.7%), and lymph node metastasis was significantly correlated with LOH (P = 0.0053). We found frequent loss at D13S260 (43.7%), D13S171 (38.6%), and D13S267 (43.6%) on 13q12-13. Among these markers, LOH at D13S171 showed a significant correlation with lymph node metastasis (P = 0.0441). Because these markers flank the BRCA2 gene, we intensively examined a mutation of the gene through all coding exons and exon-intron junctions by PCR-single-strand conformational polymorphism analysis under two different assays. We found only seven nucleotide substitutions as normal polymorphic changes; tumor-specific mutations were not detected, and loss of expression was not observed, indicating that the BRCA2 gene might not be a target of allelic loss in this region. Relatively frequent LOH was also found at the RB1 locus (34.7%), but a significant correlation with lymph node metastasis was not observed (P = 0.7430). Protein expression of RB1 was examined in 31 ESC cell lines, and loss of expression was infrequent (6.5%), indicating that inactivation of the RB1 gene might not be responsible for lymph node metastasis. Taken together, allelic loss at 13q12-13 of the primary ESC was closely associated with lymph node metastasis, and unidentified tumor suppressor gene(s) in this region might be involved.     

Gain of distal chromosome arm 17q is not associated with poor prognosis in neuroblastoma.

PURPOSE: In several studies, gain of the distal long arm of chromosome 17 was shown to be a frequent and prognostically relevant factor in neuroblastoma, in addition to MYCN amplification (MNA) or 1p deletion. We asked whether this observation could be confirmed in a German cohort. EXPERIMENTAL DESIGN: To evaluate the frequency and prognostic impact of 17q gain, we investigated tissue samples from 193 neuroblastoma patients by the use of fluorescence in situ hybridization. The DNA probe (MPO) was located in distal 17q in the region of interest as used by several groups. To analyze the association of patients' outcome with the breakpoint position within 17q, we used the more proximal DNA probe ERBB2 in 17q21 on a selected number of cases. Gain was defined as an excess of 17q material compared with the chromosome 17 centromere in at least 50% of the analyzed tumor cells. In addition, alterations in chromosomes 1p, 3p, and 11q, as well as MYCN status, were determined to describe the interrelationship between the different parameters and to evaluate an independent prognostic influence. RESULTS: Gain of 17q was found in 61% of the investigated tumors. An additional 23% displayed an excess of 17q in less than half of all cells. Gain correlated with stage 4 disease (P = 0.003) and with other chromosomal alterations, such as 1p (P < 0.001), 3p (P = 0.01), 11q (P = 0.001), and MNA (P = 0.016), as well as with increased patient age (P = 0.01). Outcome was not different between patients with 17q gain compared with those without, however. A prognostic influence could not be delineated in all stages or in localized or in stage 4 subgroups or in the MYCN nonamplified patient cohort. Outcome did not differ between patients with additional 17q material in <10% of the cells or in >70%. Patients showing a breakpoint in the more proximal part of 17q could not be described as having a more favorable outcome compared with patients with a more distal breakpoint. Prognosis was poor in patients with MNA and/or 11q loss either with or without 17q gain. A multivariate analysis including the chromosomal parameters 17q, 11q, and MYCN status, as well as stage, showed MYCN and 11q status (P < 0.001), but not 17q or stage as significant prognostic factors. CONCLUSION: Although the most frequent aberration in neuroblastoma to date, we found no association between 17q gain and an inferior prognosis in our cohort; the status of MYCN and 11q, however, allowed reliable prediction of patients' outcomes.     

Amplification of genes within the chromosome 11q13 region is indicative of poor prognosis in patients with operable breast cancer.

Amplification of the chromosome 11q13 region, which harbors the BCL1 region and the PRAD1, EMS1, HSTF1, and INT2 genes, was found in 36 (16%) of a series of 226 breast carcinomas. In the 153 patients with stage I-IIIa disease who had received no therapy prior to surgery and who were treated with curative intent, 11q13 amplification was associated with the presence of lymph node metastases (P less than 0.002). The presence of an 11q13 amplification was associated with a significantly shorter relapse-free survival (P less than 0.002) and a higher breast cancer-specific mortality (P less than 0.003). Stepwise multivariate analysis showed that, in addition to lymph node status, 11q13 amplification was the best predictor for short survival. Stratified log-rank analysis indicated that, within the group of lymph node-positive breast cancer patients, 11q13 amplification identifies a subgroup at high risk.     

Correlation analysis between loss of heterozygosity at chromosome 18q and prognosis in the stage-Ⅱ colon cancer patients

Background and Objective: Colorectal cancer is one of the most common malignant cancers in the world. Although the clinicopathologic staging is the golden criterion for the prognosis at present, the optimum prognostic criteria for colorectal cancer should be a combination of the clinicopathologic staging and the molecular markers. However, there are currently no molecular markers available for the prognosis of colorectal cancer. Several tumor-suppressor genes associated with colorectal cancer have been mapp...     

Allelic loss on distal chromosome 17p is associated with poor prognosis in a group of Brazilian breast cancer patients.

We examined loss of heterozygosity (LOH) for two loci on chromosome 17p (D17S5 and TP53), and erbB-2 gene amplification, in primary breast cancers from 67 Brazilian patients. We identified two distinct regions of LOH on chromosome 17p, one spanning TP53 and the other a more telomeric region (D17S5). Based on a short-term follow-up, Kaplan-Meier analyses of patients'' disease-free survival showed that patients with LOH for D17S5, but retaining heterozygosity for TP53, were at higher risk of recurrence (P = 0.007) than those who retained heterozygosity for D17S5. Bivariate analyses indicated that patients with LOH for D17S5 alone had an increased risk of recurrence (hazard ratio = 7.2) over patients with erbB-2 amplification (hazard ratio = 3.7), when compared with patients with neither alteration (hazard ratio = 1.0). Further, lymph node-positive patients whose tumours had both LOH for D17S5 and erbB-2 gene amplification had a higher risk of recurrence than patients whose tumours had neither of these genetic alterations. Our data confirm previous reports of a putative tumour-suppressor gene, distinct from TP53, on distal chromosome 17p which is associated with breast cancer. They further suggest that LOH for loci in this region may provide an independent indicator to identify patients with poor prognosis.     

Clinicopathological significance of loss of heterozygosity on chromosome 13q in hepatocellular carcinoma.

PURPOSE: Allelic loss is the most frequently genetic alteration found in hepatocellular carcinoma (HCC). Previous genome-wide studies have indicated that chromosome 13q is one of the most frequently affected chromosomes. However, reports on detailed deletion mapping as well as detailed clinicopathological correlation are scanty. EXPERIMENTAL DESIGN: We performed high-density allelotyping on chromosome 13q in HCC from 60 patients and investigated the correlation between allelic losses on chromosome 13q and the clinicopathological features. RESULTS: Allelic loss at one or more of the 29 microsatellite markers was found in 28 (47%) of the 60 HCCs. Allelic losses were more frequently found in tumors with larger size or in tumors at more advanced tumor stages (P = 0.015 and 0.012, respectively). These two clinicopathological features were also significantly associated with the accumulation of allelic losses in terms of fractional allelic loss index (P = 0.028 and 0.018, respectively). In addition, subchromosomal regions located at 13q12.3-14.1 and 13q32 were found to be significantly associated with advanced tumor stages and larger tumor size, respectively (P = 0.008 and 0.007). CONCLUSIONS: The overall findings suggested that allelic losses on 13q might play an important role in contributing to a more aggressive tumor behavior. Putative tumor suppressor genes might be harbored at 13q12.3-14.1 and 13q32, and inactivation of these genes via allelic losses might enhance tumor progression in HCC.     

Loss of SFRP1 is associated with breast cancer progression and poor prognosis in early stage tumors

Aberrant activation of the Wnt signaling pathway plays an important role in the development of solid tumors such as breast and colon cancer. Secreted Frizzled-related protein 1 (SFRP1) is a negative regulator of the Wnt pathway. It has been described that SFRP1 mRNA is strongly down-regulated in breast cancer and a putative tumor suppressor function has been postulated. We have generated and characterized an SFRP1 specific antibody to analyze its expression on protein level and to investigate the association of SFRP1 expression with clinicopathological parameters and patient survival. Analysis of >2000 invasive breast tumors and 56 carcinoma in situ revealed similar frequencies of SFRP1 loss in these tumors (46% and 43% respectively). Therefore, we propose that loss of SFRP1 expression is an early event in breast tumorigenesis. SFRP1 expression was inversely correlated with tumor stage (p<0.001) but not with tumor grade (p=0.14) or lymph node status (p=0.84). Performing a multivariate analysis we could confirm the association between tumor stage and SFRP1 expression (p=0.029). In particular, loss of SFRP1 expression in early stage breast tumors (pT1) was associated with poor prognosis (p=0.04). In conclusion, expression of SFRP1 is commonly lost in breast cancer. SFRP1 expression might be useful as a novel prognostic marker in early stage breast cancer.     

Loss of heterozygosity on chromosome 10q associated with malignancy and prognosis in astrocytic tumors, and discovery of novel loss regions

Certain tumor suppressor genes (TSG) residing on human chromosome 10q are implicated in astrocytic tumors. We thoroughly examined loss of heterozygosity (LOH) on chromosome 10q in astrocytic tumors to determine the extent of deletion and their relation to prognostic variables of patients. We analyzed 63 astrocytic tumors, including 9 diffuse astrocytomas, 36 anaplastic astrocytomas, and 18 glioblastomas. DNAs from tumors and leukocytes were analyzed for LOH at 18 microsatellite loci by polymerase chain reaction using fluorescence-labeled primers. Then correlation between LOH and clinicopathological variables was examined statistically. Twenty-four (66.7%) anaplastic astrocytomas and 15 (83.3%) glioblastomas had at least one LOH on chromosome 10q. However, diffuse astrocytomas exhibited no LOH. Nineteen tumors (10 anaplastic astrocytomas and 9 glioblastomas) were believed to have a total loss of one chromosome 10. Analyses on 20 tumors with interstitial LOH revealed that most of the high LOH regions matched the location of known TSGs, while some novel LOH regions were found preferentially in anaplastic astrocytoma. The median survivals of the total, partial, and no loss groups were 10.1, 14.8, and 46.8 months, respectively, indicating a significant difference in the survivals of these groups (P=0.0289). Thus, analyzing chromosome 10q loss is helpful for diagnosing malignancy in astrocytic tumors and for predicting patients' survival. Our data also suggested that there are novel TSGs for anaplastic astrocytoma at 10q24 and 10q26.     

Arpin downregulation in breast cancer is associated with poor prognosis

Background:

The Arp2/3 complex is required for cell migration and invasion. The Arp2/3 complex and its activators, such as the WAVE complex, are deregulated in diverse cancers. Here we investigate the expression of Arpin, the Arp2/3 inhibitory protein that antagonises the WAVE complex.

Methods:

We used qRT–PCR and reverse phase protein arrays in a patient cohort with known clinical parameters and outcome, immunofluorescence in breast biopsy cryosections and breast cancer cell lines.

Results:

Arpin was downregulated at the mRNA and protein levels in mammary carcinoma cells. Arpin mRNA downregulation was associated with poor metastasis-free survival (MFS) on univariate analysis (P=0.022). High expression of the NCKAP1 gene that encodes a WAVE complex subunit was also associated with poor MFS on univariate analysis (P=0.0037) and was mutually exclusive with Arpin low. Arpin low or NCKAP1 high was an independent prognosis factor on multivariate analysis (P=0.0012) and was strongly associated with poor MFS (P=0.000064).

Conclusions:

Loss of the Arp2/3 inhibitory protein Arpin produces a similar poor outcome in breast cancer as high expression of the NCKAP1 subunit of the Arp2/3 activatory WAVE complex.     

A loss of c-kit expression is associated with an advanced stage and poor prognosis in breast cancer

To evaluate the c-kit expression in breast cancer, 217 invasive ductal carcinomas of the breast were immunohistochemically stained for c-kit protein. The c-kit expression was positive in 59 (27%) of 217 tumours, while the c-kit expression was negative in 158 (73%) of 217 tumours. There was a significant correlation between a negative expression of the c-kit protein and lymph node metastasis (P < 0.0001), and the incidence of a negative expression of the c-kit protein increased as the number of the metastatic lymph nodes increased (P = 0.0003). The c-kit expression did not significantly correlate with the tumour size, nuclear grade, oestrogen receptor status, MIB-1 counts and p53 protein expression. A univariate analysis indicated the patients with the negative c-kit expression to have a worse disease-free survival (DFS) than those with the positive c-kit expression (P = 0.0041), while a multivariate analysis determined lymph node metastases and the MIB-1 counts to be independently significant factors for DFS. In conclusion, a loss of the c-kit expression was found in about three-fourth of invasive ductal carcinoma of the breast and was associated with lymph node metastases. The prognostic implications of the c-kit expression seem to be due to fact that a loss of the c-kit expression is associated with an advanced stage of breast cancer.