Amplification of protooncogenes in human ovarian carcinomas

Amplification of the proto-oncogenes c-myc, c-erbB2, c-K-ras2, c-H-ras1, c-erbA1, c-int2 and c-fms was studied by Southern-blot analysis of DNA extracted from 27 primary ovarian carcinomas. In addition, karyotype analysis and interphase cytogenetics using fluorescence in situ hybridization (FISH) were applied to control the chromosomal variability of the tumors. By these additional analyses the possibility of a false estimation of the grades of amplification should be diminished. In nearly 50% of the studied tumors a low to moderate (2- to 10-fold) amplification of one or more oncogenes was detected. The proto-oncogene amplified most frequently was c-myc (11 tumors), followed by c-erbB2 and c-Kras2 (3 tumors each), c-fms (2 tumors), and c-int2 (1 tumor). Neither an amplification of c-erbA1 nor of c-H-ras1 could be detected in any of the tumors. Some of the tumors showed a simultaneous amplification of two or three oncogenes. The pattern of proto-oncogene amplification clearly differentiates the studied ovarian cancers from breast tumors, but also differs from some previous results obtained from ovarian carcinomas.     

High correlation between molecular alterations of the c-myc oncogene and carcinoma of the uterine cervix

We have examined 35 human tumors of the uterine cervix (carcinoma presenting the highest incidence in Mexico; about 34% of women's malignant tumors) for alterations of the cellular myc (c-myc) protooncogene. Elevated amplification and/or rearrangement of the c-myc oncogene were detected in most (approximately 90%) samples (48% showed amplification and 43% presented both alterations). Most tumors were stage II cervical carcinomas and for some of them we detected up to 60-fold amplification of c-myc. These results suggest an important role for c-myc oncogene in the development of tumors of the uterine cervix.     

Proto-oncogene amplification and human breast tumor phenotype

Amplification of c-myc, c-erbB-2, hst and int-2 proto-oncogenes was investigated in two independently collected breast tumor series comprising 292 carcinomas. Differences in the frequencies of amplification could be observed between these two series for c-myc (9.3% vs. 20.8%) and hst/int-2 (21.5% vs. 15.6%) whereas similar values were found for c-erbB-2 (22.5% vs. 20.3%). Statistical correlations between amplification and disease parameters were also dependent on population sampling. Therefore we performed our statistical analysis on the pooled populations and focused on the 219 primary breast carcinomas from patients without therapy prior to surgery. Amplification of c-erbB-2 was strongly correlated to the absence of either estrogen (ER-, P = 0.003) or progesterone (PR-, P = 0.004) receptors. An amplified c-myc was significantly associated with PR- (P = 0.005) and was prevalent in high grade tumors. On the contrary, hst/int-2 amplification was correlated to PR+ tumors (P = 0.01) and was more frequent in ER+ and low grade tumors, and was also correlated with lymph node involvement (P = 0.04). Our data suggest that amplification of each of these proto-oncogenes could be representative of a particular subset of breast tumors. Therefore, proto-oncogene amplification may be helpful in characterizing new biological subclasses in human breast cancer.     

Genetic alterations of c-myc, c-erbB-2, and c-Ha-ras protooncogenes and clinical associations in human breast carcinomas

We have analyzed genomic DNA sequences from 125 prospectively collected single unilateral primary breast carcinoma samples for the presence of alterations of c-myc, c-erbB-1, c-erbB-2, c-Ki-ras and c-Ha-ras protooncogenes. Amplification of the c-myc gene was found in 18% of the samples, and in one sample a non-germ line c-myc related DNA fragment or rearrangement was detected. We have found a significant association (P = 0.0010) between amplified c-myc gene and inflammatory carcinoma, a particularly aggressive breast cancer. The c-erbB-2 gene was amplified in 22% of the tumor samples and a rearrangement was observed once. Alteration of the c-erbB-2 gene was significantly linked to histological grade III tumors (P = 0.005) and the absence of estrogen and progesterone receptors (P = 0.036). No amplifications were observed for c-erbB-1, c-Ki-ras, and c-Ha-ras genes. About 40% of breast carcinomas contain either amplified c-myc or c-erbB-2 protooncogenes, whereas simultaneous amplification of both was seen in only one sample, suggesting the involvement of two distinct molecular mechanisms in breast cancer. Comparison of DNA from peripheral blood and tumor samples indicated loss of one c-Ha-ras allele in 29% of patients heterozygous for this polymorphism. A significant correlation (P = 0.016) between c-Ha-ras locus (11p14) allele loss and patient survival was found. These data suggest that 11p14 allelic loss plays a role in the evolution of human breast cancer, amplification of c-erbB-2 gene is associated with increasing stage of malignancy, and alteration of the c-myc gene in inflammatory breast carcinoma may contribute to the rapid progression of this human tumor subtype.     

Presence of two members of c-erbA receptor gene family (c-erbA beta and c-erbA2) in smallest region of somatic homozygosity on chromosome 3p21-p25 in human breast carcinoma

The loss of heterozygosity of genes on the short arm of chromosome 3 (3p) in human breast carcinomas occurs in a region involved in other malignancies, including renal cell carcinoma, lung cancers, and von Hippel-Lindau disease. This finding suggests the presence of a gene(s) that plays a crucial role in multiple cancers. In our study of 84 informative (heterozygous) primary breast tumors, 30% showed losses of heterozygosity on chromosome 3. The shortest region of homozygosity in primary human breast tumor is located between the DNF15S2 and RAF1 loci in the 3p21-p25 region on the short arm of chromosome 3. This region includes at least two members of the c-erbA steroid/thyroid hormone receptor family (c-erbA beta and c-erbA2) that may be of special relevance to breast cancer. Furthermore, tumors with a loss of heterozygosity of genes on chromosome 3 were previously reported to have frequent allelic deletions on chromosome 11p and amplification of the c-myc proto-oncogene. These results highlight the occurrence of multiple genetic alterations in breast tumors.     

弥漫大B细胞淋巴瘤myc、bcl-2和bcl-6蛋白表达与基因异常的相关性研究

目的 探讨多重基因异常在弥漫大B细胞淋巴瘤(DLBCL)中的发生情况及其与蛋白高表达之间的关系.方法 收集2012年1月至2016年12月确诊的DLBCL非特指型患者50例,采用免疫组织化学法检测c-myc、bcl-2及bcl-6蛋白表达情况,采用间期荧光原位杂交(I-FISH)方法检测3个基因异常情况.结果 50例DLBCL患者中,男性27例,女性23例;年龄3~85岁,中位年龄50岁.发病部位:淋巴结23例(46.00%),结外27例(54.00%),以胃肠道最为多见(13例,48.15%).免疫组织化学检测c-myc蛋白阳性率94.00%(47/50),阳性细胞超过40%者41例(82.00%);bcl-2蛋白阳性率84.00%(42/50),阳性细胞超过70%者38例(76.00%);18例(36.00%)同时高表达c-myc和bcl-2.FISH检测结果显示,7例(14.00%)c-myc断裂,2例(4.00%)扩增;6例(12.00%)bcl-2断裂,4例(8.00%)扩增;8例(16.00%)bcl-6断裂,3例(6.00%)扩增,1例(2.00%)同时断裂及扩增;4例(8.00%)检测到多重基因异常,其中1例(2.00%)c-myc合并bcl-2基因异常,2例(4.00%)c-myc合并bcl-6基因异常,为双重打击淋巴瘤(DHL),1例(2.00%)同时检测到c-myc、bcl-2及bcl-6基因异常,为三重打击淋巴瘤(THL).4例多重基因异常病例中,3例起源于生发中心B细胞(GCB),1例起源于非GCB.18例c-myc和bcl-2蛋白双高表达组仅有3例(16.67%)检测到多重基因异常,包括2例DHL和1例THL.结论 多重基因异常在DLBCL中的检出率为8.00%.基因异常与蛋白高表达之间无明显相关性,DHL的检出依赖于分子遗传学检测.     

Heterogeneity of lung cancer cells with respect to the amplification and rearrangement of myc family oncogenes

Seventy lung tumors from 53 patients were analysed for alterations of myc family oncogenes, c-myc, N-myc and L-myc, to evaluate when activation of these genes occurs during tumor development. The 53 cases were 17 small cell carcinomas (SCCs), 18 adenocarcinomas, 12 squamous cell carcinomas (SqCs), 4 large cell carcinomas and 2 adenosquamous carcinomas. Either N-myc or L-myc was amplified in 4 of the 17 (one N-myc and 3 L-myc) SCCs (24%), while c-myc was amplified in 3 of the 12 SqCs (25%). In one SCC, amplification of N-myc was found in the primary tumor, a pulmonary hilar lymph node metastasis and a pleural metastasis, but not in a liver metastasis or a para-aortic lymph node metastasis. In one SqC, c-myc was amplified in a pleural metastasis and a lymph node metastasis, but not in the primary tumor. In 2 cases of SCCs, amplification or rearrangement of c-myc was detected only in the cell lines, but not in the original tumors taken from the same individuals. These results indicate that tumor cells were heterogeneous for amplification and rearrangement of myc family oncogenes, and suggest that activation of these oncogenes in SCCs and SqCs occurs not at the time of malignant transformation but during tumor progression.     

Evaluation of c-myc proto-oncogene in primary human breast carcinomas.

The expression of the c-myc proto-oncogene product was examined by immunohistochemistry in 11 normal breast tissues, 31 invasive and 14 non-invasive breast carcinomas. The c-myc product was detected in all breast carcinoma specimens and in seven of 11 normal breast tissues. Invasive tumors stained more frequently with the anti-myc monoclonal antibody (MAb) than non-invasive tumors, while the level of expression in normal breast tissue was much less than that in a breast cancer. Marked heterogeneity in the c-myc expression was seen among different tumors and within individual tumors. None of the eight invasive tumors with a high protein level of the c-myc showed evidence of gene amplification by Southern blot analysis.     

Analysis of C-myc amplification by the differential polymerase chain-reaction (d-PCR), study in breast-cancer

c-myc proto-oncogene amplification seems to have a prognostic value in breast cancer. In this study, quantitative analysis of c-myc amplification was carried out by differential polymerase chain reaction technique (d-PCR) using beta-globin as the reference gene. d-PCR assessment showed coampIification products of c-myc and beta-globin depend on variations in reaction factors such as the genomic DNA concentration, the relative concentrations of the various amplimers, the thermostable DNA polymerase concentration and the number of cycles. However, amplification of c-myc can be estimated quantitatively. In addition, results of individual sets of d-PCR can be expressed on a standard reference scale. A clinical study of 309 patients with breast cancer found c-myc amplification, respectively in 19% (45/236) of primary tumour tissues, 21% (4/19) of subsequent second primary cancers, 36% (4/11) of tumours of patients with bilateral lesions, 40% (8/20) of local recurrence tumours and 22% (5/23) of metastatic lesions. Amplification of c-myc was observed more frequently in histological grades 2-3 (p<0.02), in ER negative (p<0.01) and PgR negative tumours (p<0.02), but was not associated with age, tumour size, nodal status, histology, cytosolic cathepsin D or pS2. d-PCR appears amenable to automation and should facilitate large scale, inter laboratory gene amplification studies.     

Coexpression of C-erbb2 and int-2 oncogenes in invasive breast-cancer

Invasive breast carcinomas of 19 premenopausal and 49 postmenopausal women were studied by Southern blot analysis for detection of c-erbB2 and int-2 oncogenes, and quantitation of c-erbB2 protein, p185 by ELISA. The data were correlated with the histological grade of the tumor and the patient's clinical status. Seventeen tumors (25.0%) showed genomic alteration in one or both oncogenes. c-erbB2 and int-2 amplification were expressed by 10 (14.7%) and 7 (10.2%) of the tumors respectively. c-erbB2 overexpression was found in 15 out of 68 tumors (22.1%). All tumors exhibiting amplification of c-erbB2 also showed overexpression of p185 protein, however 5 out of 15 tumors (33.3%) showing c-erbB2 overexpression did not show amplification. Rearrangement of c-erbB2 and int-2 oncogenes was observed in 4 out of 68 tumors (5.9%) and 2 of these tumors presented rearrangement of both oncogenes. A significant positive correlation was found between c-erbB2 amplification and p185 protein overexpression, and c-erbB2 and int-2 amplification. Oncogene alterations were more frequently detected in tumors with high histological grade, but no correlation was found with patient's age, menopausal or lymph node status.     

The significance of oncogene amplification in primary breast cancer

Alterations in the gene copy numbers of the proto-oncogenes HER2/neu and c-myc in primary human breast cancer investigated in 73 patients. We detected amplification of HER2/neu in 17 patient samples and amplification of c-myc in 11, while amplification of both was seen in 6 samples. There was no correlation of age, hormone receptor positivity or tumour size with amplification of either proto-oncogene. Amplification of HER2/neu was significantly correlated with the stage of the disease. HER2/neu amplification was observed in 18.5% and 38% of node-negative and node-positive patients, respectively; the association between HER2/neu amplification and advanced stage of the disease was statistically significant (p = 0.05). Since this is a prospective study, the clinical significance of oncogene amplification is not known. The relatively high frequency of HER2/neu amplification points to a functional role in human breast cancer, particularly in the progression of the disease. The method used in our study allows oncogene amplification to be studied in conjunction with hormone receptor determination and thus may be of value in large clinical trials to determine the significance of oncogene abnormalities in breast cancer.     

Amplification of c-myc in hepatocellular carcinoma: correlation with clinicopathologic features, proliferative activity and p53 overexpression.

Expression of the proto-oncogene c-myc has been implicated in liver regeneration and hepatocarcinogenesis. The biologic significance of c-myc gene amplification in human hepatocellular carcinoma, however, is unconfirmed. We correlated c-myc gene amplification with clinicopathologic features, proliferative activity, and p53 expression in 42 resected tumors. c-myc amplification in tumor tissue was determined using a differential polymerase chain reaction, a useful procedure for the evaluation of gene amplification in archival formalin-fixed paraffin-embedded tissues, in comparison with a dopamine D2 receptor gene. Proliferative activity was estimated by numbers of argyrophilic nucleolar organizer regions and immunohistochemical nuclear labeling rates using a monoclonal antibody against Ki-67. The c-myc gene was amplified in 14 of 42 tumors (33.3%). Amplification of c-myc was more frequent in younger patients and in larger tumors, and less differentiated tumors. No correlation was noted with alpha-fetoprotein level or viral hepatitis state. The amplification showed positive correlation with both proliferative activity and p53 overexpression. Disease-free survival in patients showing c-myc amplification was significantly shorter than in those without amplification. These results suggest that c-myc amplification is an indicator of malignant potential and poor prognosis in hepatocellular carcinoma. c-myc amplification and p53 alteration may be coparticipating events in the progression of these tumors.     

Heterogeneous protooncogene amplification correlates with tumor progression and presence of metastases in gastric cancer patients

In order to evaluate the relevance of protooncogene alterations in gastric cancer and to specifically relate these alterations to types and stages of the neoplasia, we studied oncogenes of possible interest in gastric tumors with different clinical parameters. Fifty DNAs from primary gastric adenocarcinoma were analyzed, by the Southern blotting technique, for the presence of amplification or rearrangements of seven different protooncogenes: c-myc, c-erbB2, c-Ki-ras, c-Ha-ras, c-N-ras, hst, and c-mos. All the tumors analyzed were histologically classified and staged. Amplification of the following genes was found: c-myc (2 of 50), hst (3 of 50), c-erbB2 (3 of 50), and c-Ki-ras (5 of 50). The simultaneous amplification of hst (3 cases), c-myc (1 of 3), or c-Ki-ras (2 of 3) was observed. Analysis of DNAs from atrophic and metaplastic gastric mucosa (which can be regarded as preneoplastic lesions) of the 10 patients showing gene amplification demonstrated that this was limited to neoplastic cells. Considering protooncogene amplification in general (i.e., involving different genes and occurring to different degrees) and clinical parameters of tumors, we found a statistically significant association between amplification and both tumor progression and presence of metastases. Therefore, at least for the genes analyzed, amplification is a relatively infrequent phenomenon and represents a late event in the temporal development of gastric cancer.     

A unique pattern of proto-oncogene abnormalities in ovarian adenocarcinomas

Twelve cases of ovarian adenocarcinoma were studied for alterations in proto-oncogenes, and a unique pattern of altered ras proto-oncogenes was observed. Amplification of ras-Ki was found in three of seven ovarian tumors and amplification of ras-Ha in one of 12. In contrast, ras-Ha amplification was not found in any of the 334 other tumors and ras-Ki amplification was only seen in breast cancer at a frequency of 3%. Other proto-oncogenes altered in ovarian adenocarcinomas included c-myc and c-erbb-2. Proto-oncogene abnormalities were more frequent in aggressive tumors of high histologic grade.     

c-myc amplification is a better prognostic factor than HER2/neu amplification in primary breast cancer.

Amplification of the c-myc and HER2/neu genes was found in 20 and 23%, respectively, of primary breast cancer tissues derived from 282 patients (median follow-up, 74 months). c-myc amplification was observed more frequently in larger tumors (P = 0.01) and in lymph node-positive patients (P = 0.01) but was not associated with age, menopausal status, or with differentiation grade or steroid receptor status. c-myc amplification was strongly negatively correlated with HER2/neu amplification (P less than 0.001). In univariate analysis, amplification of c-myc proved to be a significant predictor of reduced relapse-free and overall survival (for both, P less than 0.001). In multivariate analysis for relapse-free survival, c-myc amplification significantly (P = 0.001) added to the prognostic power of tumor size (P less than 0.001), lymph node status (P less than 0.001), and estrogen receptor status (P = 0.003), with the highest relative failure rate (1.8) after lymph node status (2.2). In this pilot study, c-myc amplification was predictive for outcome, especially among patients with node-negative disease or steroid receptor-positive tumors; 51 and 46% differences in actuarial 5-year recurrence rates when compared to patients with tumors with normal c-myc gene copy numbers, respectively. HER2/neu amplification was not associated with relapse-free survival but weakly with shorter overall survival in univariate analysis (P = 0.035). Only in the relatively small subgroup of steroid receptor-negative tumors, HER2/neu amplification may identify those patients with an increased risk of death. In conclusion, amplification of c-myc is an independent powerful prognosticator, particularly in node-negative and steroid receptor-positive breast cancer, whereas HER2/neu amplification may be of limited prognostic value, only in steroid receptor-negative disease.     

C-myc amplification in breast cancer: a meta-analysis of its occurrence and prognostic relevance

Data from basic research suggests that amplification of the proto-oncogene c-myc is important in breast cancer pathogenesis, but its frequency of amplification and prognostic relevance in human studies have been inconsistent. In an effort to clarify the clinical significance of c-myc amplification in breast cancer, we conducted a comprehensive literature search and a meta-analysis in which 29 studies were evaluated. The weighted average frequency of c-myc amplification in breast tumours was 15.7% (95% CI = 12.5-18.8%), although estimates in individual studies exhibited significant heterogeneity, P<0.0001. C-myc amplification exhibited significant but weak associations with tumour grade (RR = 1.61), lymph-node metastasis (RR = 1.24), negative progesterone receptor status (RR = 1.27), and postmenopausal status (RR = 0.82). Amplification was significantly associated with risk of relapse and death, with pooled estimates RR = 2.05 (95% CI = 1.51-2.78) and RR = 1.74 (95% CI = 1.27-2.39), respectively. This effect did not appear to be merely a surrogate for other prognostic factors. These results suggest that c-myc amplification is relatively common in breast cancer and may provide independent prognostic information. More rigorous studies with consistent methodology are required to validate this association, and to investigate its potential as a molecular predictor of specific therapy response.     

Analysis of oncogene alterations in human endometrial carcinoma: prevalence of ras mutations

The molecular genetics of human endometrial carcinoma have yet to be defined to any significant extent. Cell lines from 11 endometrial carcinomas were examined for alterations in proto-oncogenes that might predictably be present, based on existing data from the better-characterized human carcinomas of the uterine cervix, ovary, and breast. Codons 12, 13, and 61 of the Ha-ras, Ki-ras, and N-ras genes were examined for possible point mutations, and the c-erbB2/neu, c-myc, and epidermal growth factor receptor (EGFR) genes were examined for amplification or overexpression. Ras mutations were found in seven of 11 (64%) tumors, including three in codon 61 of Ha-ras (CAG----CAT) and four in codon 12 of Ki-ras (GGT----GAT in two and GGT----GTT in two). No evidence was found for amplification or overexpression of the c-erbB2 or EGFR genes in any tumor. One tumor contained amplified c-myc sequences and exhibited relative overexpression of c-myc. These data suggest that the amplification or overexpression of several proto-oncogenes frequently observed in other human gynecologic and breast tumors are not prevalent in endometrial carcinoma and that ras gene mutations are relatively common in this tumor type.     

Alterations to either c-erbB-2(neu) or c-myc proto-oncogenes in breast carcinomas correlate with poor short-term prognosis

We have examined the genomic organisation of c-myc, N-myc, L-myc, neu and N-ras in tissue from 41 breast carcinomas, lymph node metastases from 10 of these carcinomas, one fibrosarcoma, 10 cases of benign fibrocystic breast and six fibroadenomas. We have not observed an alteration in either N-myc or N-ras in any of the samples studied. We have seen a 2-fold amplification of L=myc in DNA from one infiltrating ductal (ID) carcinoma, but otherwise we have seen no alterations to this gene. Amplification of c-myc was seen in 22% of ID breast carcinoma sample. Levels of amplification ranged from 2- to 10-fold. We have found a significant (p less than 0.02) correlation between an altered c-myc gene and a very poor short-term prognosis. Amplification of neu was seen in 19% of ID breast carcinomas, but the levels of amplification were higher than those seen for c-myc. Alterations to neu also correlated well with poor short-term prognosis (p less than 0.0002). Finally, we have observed a low level of amplification of c-myc in DNA from a benign fibrocystic breast lesion. This lesion exhibited some features characteristic of those thought to be associated with an increased risk of developing breast cancer.