DNA copy number aberrations associated with lymphovascular invasion in upper urinary tract urothelial carcinoma

Recent studies have reported that lymphovascular invasion (LVI) is a predictor of patient prognosis in upper urinary tract urothelial carcinoma (UUTUC). DNA copy number aberrations (DCNAs) identified by array-based comparative genomic hybridization (aCGH) had not previously been examined in UUTUC. We therefore examined DCNAs in UUTUC and compared them with DCNAs in LVI. We applied aCGH technology using DNA chips spotted with 4,030 BAC clones to 32 UUTUC patients. Frequent copy number gains were detected on chromosomal regions 8p23.1 and 20q13.12, whereas frequent copy number losses were detected on chromosomal regions 13q21.1, 17p13.1, 6q16.3, and 17p11.2. DCNAs occurred more frequently in tumors with LVI than in those without it (P = 0.0002), and this parameter was more closely associated with LVI than with the tumor grade or pT stage. Disease-specific survival rate was higher in tumors without LVI than in those with it (P = 0.0120); however, tumor grade and stage were not significant prognostic factors of patient outcome. These data support our hypothesis that tumors with LVI have more genetic alterations in terms of total numbers of DCNAs than those without, and provide proof that aggressive adjuvant therapy should be considered for UUTUC patients with LVI.     

Platform comparisons for identification of breast cancers with a BRCA-like copy number profile

Previously, we employed bacterial artificial chromosome (BAC) array comparative genomic hybridization (aCGH) profiles from BRCA1 and -2 mutation carriers and sporadic tumours to construct classifiers that identify tumour samples most likely to harbour BRCA1 and -2 mutations, designated ‘BRCA1 and -2-like’ tumours, respectively. The classifiers are used in clinical genetics to evaluate unclassified variants, and patients for which no good quality germline DNA is available. Furthermore, we have shown that breast cancer patients with BRCA-like tumour aCGH profiles benefit substantially from platinum-based chemotherapy, potentially due to their inability to repair DNA double strand breaks (DSB), providing a further important clinical application for the classifiers. The BAC array technology has been replaced with oligonucleotide arrays. To continue clinical use of existing classifiers, we mapped oligonucleotide aCGH data to the BAC domain, such that the oligonucleotide profiles can be employed as in the BAC classifier. We demonstrate that segmented profiles derived from oligonucleotide aCGH show high correlation with BAC aCGH profiles. Furthermore, we trained a support vector machine score to objectify aCGH profile quality. Using the mapped oligonucleotide aCGH data, we show equivalence in classification of biologically relevant cases between BAC and oligonucleotide data. Furthermore, the predicted benefit of DSB inducing chemotherapy due to a homologous recombination defect is retained. We conclude that oligonucleotide aCGH data can be mapped to and used in the previously developed and validated BAC aCGH classifiers. Our findings suggest that it is possible to map copy number data from any other technology in a similar way.     

Genome‐wide DNA methylation profiles in liver tissue at the precancerous stage and in hepatocellular carcinoma

To clarify genome‐wide DNA methylation profiles during hepatocarcinogenesis, bacterial artificial chromosome (BAC) array‐based methylated CpG island amplification was performed on 126 tissue samples. The average numbers of BAC clones showing DNA hypo‐ or hypermethylation increased from noncancerous liver tissue obtained from patients with hepatocellular carcinomas (HCCs) (N) to HCCs. N appeared to be at the precancerous stage, showing DNA methylation alterations that were correlated with the future development of HCC. Using Wilcoxon test, 25 BAC clones, whose DNA methylation status was inherited by HCCs from N and were able to discriminate 15 N samples from 10 samples of normal liver tissue obtained from patients without HCCs (C) with 100% sensitivity and specificity, were identified. The criteria using the 25 BAC clones were able to discriminate 24 additional N samples from 26 C samples in the validation set with 95.8% sensitivity and 96.2% specificity. Using Wilcoxon test, 41 BAC clones, whose DNA methylation status was able to discriminate patients who survived more than 4 years after hepatectomy from patients who suffered recurrence within 6 months and died within a year after hepatectomy, were identified. The DNA methylation status of the 41 BAC clones was correlated with the cancer‐free and overall survival rates of patients with HCC. Multivariate analysis revealed that satisfying the criteria using the 41 BAC clones was an independent predictor of overall outcome. Genome‐wide alterations of DNA methylation may participate in hepatocarcinogenesis from the precancerous stage, and DNA methylation profiling may provide optimal indicators for carcinogenetic risk estimation and prognostication. © 2009 UICC     

Genomic copy number alterations as predictive markers of systemic recurrence in breast cancer

We tried to establish models that predict systemic recurrence in breast cancer by selecting marker clones with DNA copy number alterations (CNAs) using an array comparative genomic hybridization (CGH). Array CGH containing 4,044 human bacterial artificial chromosome clones was used to assess CNAs in 62 primary breast cancer tissues from 31 patients with systemic recurrence within 5 years after surgery and clinicopathologically well matched 31 patients who had no evidence of disease for at least 5years. Fourteen significant clones (11 clones showing gain and 3 showing loss) were identified by systemic recurrence-free survival (SRFS) analysis and 23 significant clones (17 clones showing gain and 6 showing loss) identified by chi(2) test and FDR test were selected as predictive markers of systemic breast cancer recurrence. The significant CNAs were found in the chromosomal regions of 5p15.33, 11q13.3, 15q26.3, 17q25.3, 18q23 and 21q22.3 with gain and 9p12, 11q24.1 and 14q32.33 with loss. We devised 2 prediction models for the systemic recurrence of breast cancer based on the 14 clones and the 23 clones, respectively. The survivals of the patients were significantly separated according to the scores from each model at the optimal cut off values in SRFS and overall survival analysis. We found candidate clones and genes of which CNAs were significantly associated with systemic recurrence of breast cancer. The devised prediction models with these clones were effective at differentiating the recurrence and nonrecurrence.     

DNA copy number aberrations associated with the clinicopathological features of colorectal cancers: Identification of genomic biomarkers by array-based comparative genomic hybridization

The aim of the present study was to investigate the chromosomal aberrations that are linked with the crucial clinicopathological features of colorectal cancer (CRC) and its prognosis by array-based comparative genomic hybridization (CGH). Fresh-frozen tumor tissues of 94 cases of CRC were analyzed by using bacterial artificial chromosome (BAC) CGH slides spotted with 4030 human BAC clones, which covered the whole range of the human genome at an average interval of 0.83 mega base pairs. DNA copy number aberrations (DCNAs) were identified in association with clinicopathological features: a gain of 8q24.3 and losses of 9q33.1 and 20p12.2 were associated with lymph node metastasis, gain of 8q24.3 and loss of 9q33.1 with disease stage, gain of 8q21.11 and loss of 10q21.3 with lymphovascular invasion and losses of 3p25.1, 10p15.3, 12q15 and 17p13.1 for venous invasion. These aberrations can be regarded as genomic biomarkers to predict the clinical outcome of patients with CRC, and are expected to serve to individualize the treatment of CRC patients.     

Loss of 3p26.3 is an independent prognostic factor in patients with oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a common malignancy worldwide and the prognosis for patients with advanced-stage OSCC is particularly poor. To identify DNA copy number aberrations and candidate genes associated with a poor or favorable outcome, we analyzed the genome profiles of OSCC tumors by array-based comparative genomic hybrid-ization (A-CGH). This technique uses DNA microarray technology to detect genomic copy number variations at a higher resolution level than chromosome-based CGH. Fifty patients with primary OSCCs were included in the study. Of these 50 patients, 37 were treated surgically and 13 were treated without surgery and had received irradiation and/or chemotherapy. All samples were analyzed by A-CGH. Gains were detected frequently (>50%) at chromosomal regions 5p15.33, 7p22.3, 8q21.1-24.3, 9q34.3, 11q13, 16p13.3 and 20q13.3. Losses were frequently detected at 3p22, 3p14 and 4q35.2. High-level gains were recurrently (>10%) detected at each of 5p15, 7p22, 7p11, 8q24, 11q13, 11q22 and 22q11. Gains of 2p25.1, 11p15, 16p13.3, 16q24.3 and 20q13.3 were inversely correlated with nodal metastasis. In 37 of the 50 OSCC patients treated with surgery, gains of 8q12.1-24.22 and losses of 3p26.2-3 were associated with disease-specific survival (p<0.01). Loss of a 0.2 Mb chromosomal region in 3p26.3 was associated with a poor prognostic outcome in the Kaplan-Meier analysis (p<0.01 by the log-rank test). Multivariate analysis revealed that loss of 3p26.3 is an independent prognostic factor (p<0.01) of OSCC. Loss of a 0.2 Mb chromosomal region in 3p26.3 including the CHL1 (cell adhesion molecule with homology to L1CAM1) gene was identified as a novel potential marker for predicting the prognosis of patients with OSCC.     

Genetic aberrations in prostate cancer by microarray analysis

The aim of this study was to screen genetic as well as expression alterations in prostate cancer. Array comparative genomic hybridization (aCGH) to a 16K cDNA microarray was performed to analyze DNA sequence copy number alterations in 5 prostate cancer cell lines and 13 xenografts. The aCGH confirmed the previously implicated common gains and losses, such as gains at 1q, 7, 8q, 16p and 17q and losses at 2q, 4p/q, 6q, 8p, 13q, 16q, 17p and 18q, which have previously been identified by chromosomal CGH (cCGH). Because of the higher resolution of aCGH, the minimal commonly altered regions were significantly narrowed-down. For example, the gain of 8q was mapped to three independent regions, 8q13.3-q21.11, 8q22.2 and 8q24.13-q24.3. In addition, a novel recurrent gain at 9p13-q21 was identified. The concomitant expression analysis indicated that genome-wide DNA sequence copy number (gene dosage) was significantly associated with the expression level (p < 0.0001). The analyses indicated several individual genes whose expression was associated with the gene copy number. For example, gains of PTK2 and FZD6, were associated with the increased expression, whereas losses of TNFRSF10B (alias DR5) and ITGA4 with decreased expression. In conclusion, the aCGH mapping data will aid in the identification of genes altered in prostate cancer. The combined expression and copy number analysis suggested that even a low-level copy number change may have significant effect on gene expression, and thus on the development of prostate cancer.     

Genome-wide DNA methylation profiles in urothelial carcinomas and urothelia at the precancerous stage

To clarify genome-wide DNA methylation profiles during multistage urothelial carcinogenesis, bacterial artificial chromosome (BAC) array-based methylated CpG island amplification (BAMCA) was performed in 18 normal urothelia obtained from patients without urothelial carcinomas (UCs) (C), 17 noncancerous urothelia obtained from patients with UCs (N), and 40 UCs. DNA hypo- and hypermethylation on multiple BAC clones was observed even in N compared to C. Principal component analysis revealed progressive DNA methylation alterations from C to N, and to UCs. DNA methylation profiles in N obtained from patients with invasive UCs were inherited by the invasive UCs themselves, that is DNA methylation alterations in N were correlated with the development of more malignant UCs. The combination of DNA methylation status on 83 BAC clones selected by Wilcoxon test was able to completely discriminate N from C, and diagnose N as having a high risk of carcinogenesis, with 100% sensitivity and specificity. The combination of DNA methylation status on 20 BAC clones selected by Wilcoxon test was able to completely discriminate patients who suffered from recurrence after surgery from patients who did not. The combination of DNA methylation status for 11 BAC clones selected by Wilcoxon test was able to completely discriminate patients with UCs of the renal pelvis or ureter who suffered from intravesical metachronous UC development from patients who did not. Genome-wide alterations of DNA methylation may participate in urothelial carcinogenesis from the precancerous stage to UC, and DNA methylation profiling may provide optimal indicators for carcinogenetic risk estimation and prognostication. ( Cancer Sci 2009)     

Decursin chemosensitizes human multiple myeloma cells through inhibition of STAT3 signaling pathway

Early detection of lung cancer provides the highest potential for saving lives. To date, no routine screening method enabling early detection is available, which is a key factor in the disease’s high mortality rate. Copy number changes and DNA methylation alterations are good indicators of carcinogenesis and cancer prognosis. In this study, we attempted to combine profiles of DNA copy number and methylation patterns in 20 paired cancerous and noncancerous tissue samples from non-small cell lung cancer (NSCLC) patients, and we detected several clinically important genes with genetic and epigenetic relationships. Using array comparative genomic hybridization (aCGH), statistically significant differences were observed across the histological subtypes for gains at 1p31.1, 3q26.1, and 3q26.31-3q29 as well as for losses at 1p21.1, 2q33.3, 2q37.3, 3p12.3, 4q35.2, and 13q34 in squamous cell carcinoma (SQ) patients, and losses at 12q24.33 were measured in adenocarcinoma (AD) patients (p < 0.05). In an analysis of DNA methylation at 1505 autosomal CpG loci that are associated with 807 cancer-related genes, we identified six and nine loci with higher and lower DNA methylation levels, respectively, in tumor tissue compared to non-tumor lung tissues from AD patients. In addition, three loci with higher and seven loci with lower DNA methylation levels were identified in tumor tissue from SQ patients compared to non-tumor lung tissue. Subsequently, we searched for regions exhibiting concomitant hypermethylation and genomic loss in both ADs and SQs. One clone representing 7p15.2 (which includes candidate genes such as HOXA9 and HOXA11) and one target ID representing HOXA9_E252_R were detected. Quantitative real-time PCR identified the potential candidate gene HOXA9 as being down-regulated in the majority of NSCLC patients. Moreover, following HOXA9 over-expression, the invasion of representative cell lines, A549 and HCC95, were significantly inhibited. Taken together, our results show that the combined profiling analysis technique is a useful tool for identifying biomarkers in lung cancer and that HOXA9 might be a potential candidate gene for the pathogenesis and diagnosis of NSCLC patients.     

儿童伯基特淋巴瘤遗传学异常与临床关系的研究

 目的　从基因组水平探讨儿童伯基特淋巴瘤（BL）的分子遗传学异常及发病机制。方法　利用免疫组织化学及荧光原位杂交技术对21例儿童BL病例进行免疫表型、分子遗传学及EB病毒（EBV）感染的检测;采用阵列比较基因组杂交（aCGH）技术对21例BL患儿的全基因组遗传物质的获得或缺失进行检测,分析aCGH检测结果与BL患儿的EBV感染的相关性。结果　90.5 %（19／21）的BL患儿存在染色体水平的改变,并且染色体的获得多于缺失。其中超过40 %的病例存在小片段DNA的获得,部位为3q21.1、5p13.2、19q13.32、12q23.1、14q32.33、6q27、20p13、20p11.21。42.9 %（9／21）的患儿存在14q24.2大片段DNA的获得,42.9 %（9／21）的患儿存在14q32.33大片段DNA缺失。EBV（+）和EBV（-）两组染色体的改变差异无统计学意义（P≥0.05）。结论　BL患儿中存在着较为复杂的分子遗传学变化,EBV（+）和EBV（-）BL之间染色体片段的改变无差异。大部分BL病例存在14q大片段的DNA缺失与获得,其可能与BL的发病机制关系密切。     

合肥地区食管鳞状细胞癌患者HPV感染调查及HR-HPV感染与预后的关系

目的:对合肥地区食管鳞状细胞癌患者人乳头瘤病毒(HPV)感染情况进行调查分析,并探讨高危型HPV(HR-HPV)感染与患者预后的关系。方法:选取2013年06月至2019年02月本院收治的384例合肥地区食管鳞状细胞癌(包括食管鳞状上皮高级别上皮内瘤变伴癌变)患者,均行HPV检测。统计分析纳入研究患者HPV感染情况,另手术/放化疗治疗后随访1年,根据预后情况将患者分为预后良好组及预后不良组,并采用多因素Logistic回顾性分析法分析HR-HPV感染与食管鳞状细胞癌患者预后的关系。结果:384例食管鳞状细胞癌患者中HPV感染率为36.72%,其中低危HPV感染占比为9.93%,HR-HPV占比为90.07%,基因型由高到低分别为16型、18型、52型、33型、6型、51型、58型、11型;随访1年,384例食管鳞状细胞癌患者预后不良率为57.03%(219/384),预后不良组HR-HPV感染率明显高于预后良好组(P<0.05);经Logistic回顾分析显示,癌症低分化或未分化或中分化、临床分期Ⅳ期或Ⅲ期、淋巴结转移、饮酒史、HR-HPV感染均是食管鳞状细胞癌患者预后不良的危险因素(OR=3.916、2.581、4.080、3.238、4.821、2.986、3.062,P<0.05)。结论:合肥地区食管鳞状细胞癌患者HPV感染率较高,并以HPV16、18等高危型为主,且HR-HPV感染可增加食管鳞状细胞癌患者预后不良发生风险。     

A genomic copy number signature predicts radiation exposure in post‐Chernobyl breast cancer

Breast cancer is the second leading cause of cancer death among women worldwide and besides life style, age and genetic risk factors, exposure to ionizing radiation is known to increase the risk for breast cancer. Further, DNA copy number alterations (CNAs), which can result from radiation‐induced double‐strand breaks, are frequently occurring in breast cancer cells. We set out to identify a signature of CNAs discriminating breast cancers from radiation‐exposed and non‐exposed female patients. We analyzed resected breast cancer tissues from 68 exposed female Chernobyl clean‐up workers and evacuees and 68 matched non‐exposed control patients for CNAs by array comparative genomic hybridization analysis (aCGH). Using a stepwise forward–backward selection approach a non‐complex CNA signature, that is, less than ten features, was identified in the training data set, which could be subsequently validated in the validation data set (p value < 0.05). The signature consisted of nine copy number regions located on chromosomal bands 7q11.22‐11.23, 7q21.3, 16q24.3, 17q21.31, 20p11.23‐11.21, 1p21.1, 2q35, 2q35, 6p22.2. The signature was independent of any clinical characteristics of the patients. In all, we identified a CNA signature that has the potential to allow identification of radiation‐associated breast cancer at the individual level.     

High-resolution mapping of genomic imbalance and identification of gene expression profiles associated with differential chemotherapy response in serous epithelial ovarian cancer

Array comparative genomic hybridization (aCGH) and microarray expression profiling were used to subclassify DNA and RNA alterations associated with differential response to chemotherapy in ovarian cancer. Two to 4 Mb interval arrays were used to map genomic imbalances in 26 sporadic serous ovarian tumors. Cytobands 1p36, 1q42-44, 6p22.1-p21.2, 7q32.1-q34 9q33.3-q34.3, 11p15.2, 13q12.2-q13.1, 13q21.31, 17q11.2, 17q24.2-q25.3, 18q12.2, and 21q21.2-q21.3 were found to be statistically associated with chemotherapy response, and novel regions of loss at 15q11.2-q15.1 and 17q21.32-q21.33 were identified. Gene expression profiles were obtained from a subset of these tumors and identified a group of genes whose differential expression was significantly associated with drug resistance. Within this group, five genes (GAPD, HMGB2, HSC70, GRP58, and HMGB1), previously shown to form a nuclear complex associated with resistance to DNA conformation-altering chemotherapeutic drugs in in vitro systems, may represent a novel class of genes associated with in vivo drug response in ovarian cancer patients. Although RNA expression change indicated only weak DNA copy number dependence, these data illustrate the value of molecular profiling at both the RNA and DNA levels to identify small genomic regions and gene subsets that could be associated with differential chemotherapy response in ovarian cancer.     

Simultaneous copy number gains of NUPR1 and ERBB2 predicting poor prognosis in early-stage breast cancer

ABSTRACT: BACKGROUND: The full extent of chromosomal alterations and their biological implications in early breast carcinogenesis has not been well examined. In this study, we aimed to identify chromosomal alterations associated with poor prognosis in early-stage breast cancers (EBC). METHODS: A total of 145 EBCs (stage I and II) were examined in this study. We analyzed copy number alterations in a discovery set of 48 EBCs using oligoarray-comparative genomic hybridization. In addition, the recurrently altered regions (RARs) associated with poor prognosis were validated using an independent set of 97 EBCs. RESULTS: A total of 23 RARs were defined in the discovery set. Six were commonly detected in both stage I and II groups (> 50%), suggesting their connection with early breast tumorigenesis. There were gains on 1q21.2-q21.3, 8q24.13, 8q24.13-21, 8q24.3, and 8q24.3 and a loss on 8p23.1-p22. Among the 23 RARs, copy number gains on 16p11.2 (NUPR1) and 17q12 (ERBB2) showed a significant association with poor survival (P = 0.0186 and P = 0.0186, respectively). The patients simultaneously positive for both gains had a significantly worse prognosis (P = 0.0001). In the independent replication, the patients who were double-positive for NUPR1-ERBB2 gains also had a significantly poorer prognosis on multivariate analysis (HR = 7.31, 95% CI 2.65-20.15, P = 0.0001). CONCLUSIONS: The simultaneous gain of NUPR1 and ERBB2 can be a significant predictor of poor prognosis in EBC. Our study will help to elucidate the molecular mechanisms underlying early-stage breast cancer tumorigenesis. This study also highlights the potential for using combinations of copy number alterations as prognosis predictors for EBC.     

Genome-wide screening of genomic alterations and their clinicopathologic implications in non-small cell lung cancers.

PURPOSE: Although many genomic alterations have been observed in lung cancer, their clinicopathologic significance has not been thoroughly investigated. This study screened the genomic aberrations across the whole genome of non-small cell lung cancer cells with high-resolution and investigated their clinicopathologic implications. EXPERIMENTAL DESIGN: One-megabase resolution array comparative genomic hybridization was applied to 29 squamous cell carcinomas and 21 adenocarcinomas of the lung. Tumor and normal tissues were microdissected and the extracted DNA was used directly for hybridization without genomic amplification. The recurrent genomic alterations were analyzed for their association with the clinicopathologic features of lung cancer. RESULTS: Overall, 36 amplicons, 3 homozygous deletions, and 17 minimally altered regions common to many lung cancers were identified. Among them, genomic changes on 13q21, 1p32, Xq, and Yp were found to be significantly associated with clinical features such as age, stage, and disease recurrence. Kaplan-Meier survival analysis revealed that genomic changes on 10p, 16q, 9p, 13q, 6p21, and 19q13 were associated with poor survival. Multivariate analysis showed that alterations on 6p21, 7p, 9q, and 9p remained as independent predictors of poor outcome. In addition, significant correlations were observed for three pairs of minimally altered regions (19q13 and 6p21, 19p13 and 19q13, and 8p12 and 8q11), which indicated their possible collaborative roles. CONCLUSIONS: These results show that our approach is robust for high-resolution mapping of genomic alterations. The novel genomic alterations identified in this study, along with their clinicopathologic implications, would be useful to elucidate the molecular mechanisms of lung cancer and to identify reliable biomarkers for clinical application.     

OCGR array: an oral cancer genomic regional array for comparative genomic hybridization analysis

Genetic alterations have been recognized as important events in the carcinogenesis of oral squamous cell carcinoma (OSCC) and have been used as predictors of progression risk. In this study, we have designed an oral cancer-specific human bacterial artificial chromosome (BAC) array, called the oral cancer genomic regional array (OCGR), to detect and fine map copy number alterations in OSCC. This array contains a total of approximately 45 Mbp coverage of nine chromosomal regions reported to be involved in the progression of oral cancer. We demonstrate the detection of copy number alterations in 14 microdissected clinical specimens in each of the nine regions. These include both copy number increases and decreases. Although the number of regions selected for this first generation array is small, we observed multiple segmental changes. In some cases, we observed single BAC clone alterations at 7p11 and 11q13 which contain EGFR and cyclin D1 respectively highlighting the need for high resolution detection techniques. Array comparative genomic hybridization (CGH) complements traditional methods for detecting genetic alterations in OSCC (such as microsatellite and CGH analysis) by improving the detection of segmental copy number alterations to single BAC clone resolution. This work represents the first attempt at the construction of an oral cancer-specific CGH array.     

非特指型外周T细胞淋巴瘤的染色体异常:基于基因芯片的比较基因组杂交研究

 目的　研究非特指型外周T细胞淋巴瘤（PTCL-NOS）的分子遗传学改变特征,从而为揭示其发生、发展的分子机制及治疗提供科学依据。方法　应用1Mb Array-CGH检测37例PTCL-NOS染色体改变, 并经Tile path Array-CGH 验证其结果。根据克隆性分析结果、形态学特征和提取DNA质量,最终确定31例为研究对象。结果　31例中的17例（55 %）存在染色体异常改变,包含重现性染色体片段的异常（≥4例）。其中最频发性染色体获得区域是1p36.13-1p36.32,7q22.1,7q36.1-7q36.3,7q32.1-7q32.3,7q22.1-7q34,9p11.2-9q12和9q33.3-9q34.3;最为频发性染色体缺失区域是1p12-1p21.1和13q14.11-13q14.3;另外,还发现多倍体和单倍体。结论　PTCL-NOS存在多发性重现性染色体畸变,其中携有染色体畸变频发（≥6个区域）的病例预后不良。     

Distinct genomic profiles in hereditary breast tumors identified by array-based comparative genomic hybridization

Mutations in BRCA1 and BRCA2 account for a significant proportion of hereditary breast cancers. Earlier studies have shown that inherited and sporadic tumors progress along different somatic genetic pathways and that global gene expression profiles distinguish between these groups. To determine whether genomic profiles similarly discriminate among BRCA1, BRCA2, and sporadic tumors, we established DNA copy number profiles using comparative genomic hybridization to BAC-clone microarrays providing <1 Mb resolution. Tumor DNA was obtained from BRCA1 (n = 14) and BRCA2 (n = 12) mutation carriers, as well as sporadic cases (n = 26). Overall, BRCA1 tumors had a higher frequency of copy number alterations than sporadic breast cancers (P = 0.00078). In particular, frequent losses on 4p, 4q, and 5q in BRCA1 tumors and frequent gains on 7p and 17q24 in BRCA2 tumors distinguish these from sporadic tumors. Distinct amplicons at 3q27.1-q27.3 were identified in BRCA1 tumors and at 17q23.3-q24.2 in BRCA2 tumors. A homozygous deletion on 5q12.1 was found in a BRCA1 tumor. Using a set of 169 BAC clones that detect significantly (P < 0.001) different frequencies of copy number changes in inherited and sporadic tumors, these could be discriminated into separate groups using hierarchical clustering. By comparing DNA copy number and RNA expression for genes in these regions, several candidate genes affected by up- or down-regulation were identified. Moreover, using support vector machines, we correctly classified BRCA1 and BRCA2 tumors (P < 0.0000004 and 0.00005, respectively). Further validation may prove this tumor classifier to be useful for selecting familial breast cancer cases for further mutation screening, particularly, as these data can be obtained using archival tissue.