Negative implication of C-MYC as an amplification target in esophageal cancer.

Chromosomal aberrations (amplifications and deletions) underlie the genesis or development of cancer. Amplification of 8q24 is one of the most frequent events in esophageal cancer. To define whether C-MYC is the target gene for 8q24 amplification, we performed fluorescence in situ hybridization using a MYC (8q24.12 approximately q24.13) probe in esophageal cancer from southern China. Furthermore, we detected the expression status of several genes including C-MYC, TRIB1 (alias C8FW), and FAM84B (alias NSE2) in the regions of 8q24 via reverse transcriptase-polymerase chain reaction or immunohistochemical analysis (or both). Distinct amplification of 8q24 was found in esophageal carcinomas. Only 4 of 46 cases showed obvious protein expression in part of the esophageal cancerous nest. In particular, increased protein expression of C-MYC was shown only in a small part of a cancerous nest in the four cases. Positive C-MYC staining was detected mainly in the cytoplasm of esophageal cancer cells. No expression of TRIB1 was detected in esophageal squamous cell carcinomas. Of 59 cases, 39 (66%) cases showed increased expression of FAM84B in esophageal carcinomas. The results suggest that C-MYC and TRIB1 may not be the amplification target of 8q24 in esophageal cancer. FAM84B might be involved in the genesis or development of esophageal cancer in southern China. Whether FAM84B is the amplification target of esophageal cancer awaits further investigation.

[Identification of stage Ib specific related genes in lung squamous cell cancer by oligonucleotide array].

OBJECTIVE: To establish gene expression profile of stage Ib and IIIa primary lung squamous cell cancer (SCC) within whole genome and identify genes specifically expressed in stage Ib of SCC. METHODS: Total RNA was extracted from the normal, stage Ib and IIIa lung SCC tissue. cRNA probes prepared from total RNA were hybridized with pretreatment oligonucleotide chip containing 22215 genes. The resultant data were treated with MSV 5.0 software and looked up on the affymetrix website. RT-PCR examination were used to validated the results from chip analysis. RESULTS: Comparing with the normal lung, difference genes expressed in Ib SCC are totally 1764, among which 571 were upregulated and 1193 were downregulated, and in stage IIIa, they are 554, 128 and 426 genes respectively. Genes specifically expressed in stage Ib were totally 1329, including 482 upregulation genes and 847 downregulation genes, which were classified into different category which included 480 metabolism related genes, 227 signal transduction genes, 136 cell proliferation genes, 136 immune related genes, 94 cell adhere genes, 88 transcription regulation genes, 86 cell cycle genes, 73 cytoskeleton genes, 45 differentiation genes, 42 apoptosis and 31 extracellular matrix genes. RT-PCR examination of FOXM1 and TNXB genes was consistent with the analysis of gene chip. CONCLUSION: Stage Ib and IIIa Gene expression profile of primary SCC within the whole genome were set up and genes specifically expressed in stage Ib of SCC were identified, which lay a foundation for further research on carcinogenesis mechanism and identifying new markers of early diagnosis.

Progression analysis of lung squamous cell carcinomas by comparative genomic hybridization.

OBJECTIVE: The genetic mechanisms underlying the development and progression of lung squamous cell carcinoma (SCC), the major subtype of non-small cell lung cancer, are still unknown. To better understand this disease, we studied the association between genetic alterations and the progression of lung SCC. METHODS: Chromosomal aberrations in 39 samples of lung SCC, including 21 nonmetastatic and 18 metastatic carcinomas, were characterized by comparative genomic hybridization and statistically correlated to clinical staging and metastatic ability. RESULTS: The average gains and losses per patient were significantly higher in the advanced-stage lung SCC and metastatic SCC group compared to the early-stage lung SCC and nonmetastatic SCC group. Gains of 2p, 20p and losses of 2q, 4q, 5q, 9q, 13p, 18q correlated with advanced-stage lung SCC. Losses on 2q, 4q, 6p, 16p, 16q, 18q, 20q, 21q and gains on 2p, 7p, 7q, 20p were more frequent in the metastatic SCC group, which was significantly different from the nonmetastatic SCC group. Gains on 2p, 20p and losses on 2q, 4q, 18q were not only associated with an advanced clinical stage but also with metastases of lung SCC. CONCLUSIONS: The results suggest that several chromosomal aberrations (e.g. gains on 2p, 20p and losses on 2q, 4q, 18q) may contribute to the progression of lung SCC.

[Chromosomal imbalance in primary lung squamous cell carcinoma and their relationship with smoking].

BACKGROUND & OBJECTIVE: Chromosomal imbalance plays an important role in tumorigenesis of lung cancer, and may be influenced by different carcinogens. This study was to examine chromosomal imbalance in primary lung squamous cell carcinoma (LSCC), and their association with smoking. METHODS: Chromosomal gains and losses in 39 specimens of LSCC were identified by comparative genomic hybridization (CGH), the association between chromosomal imbalances in LSCC and smoking was analyzed. RESULTS: The most frequent chromosomal gains of LSCC were detected on chromosomal arms 3q (74.4%, 29/39), 5p (66.7%, 26/39), 1q (43.6%, 17/39), 8q (41.0%, 16/39), 12p (42.6%, 18/39), 2p (38.5%, 15/39), and 18p (33.3%, 13/39), with minimal amplified regions (MAR) at 3q26.2-29 (74.4%, 29/39), 5p14.3-15.3 (66.7%, 26/39), 1q41-44(41.0%, 16/39), 8q23 (41.0%, 16/39), 12p13 (41.0%, 16/39), and 18p11.2 (33.3%, 13/39)u high-copy-number amplification at chromosomal arms 3q, and 5p were found in 15 (38.5%), and 6 (15.4%) patients. Chromosomal losses mainly involved chromosomal arms 3p (56.4%, 22/39), 5q (53.8%, 21/39), 13q (51.3%, 20/39), 8p (46.1%, 18/39), 4p (43.6%, 17/39), 4q (43.6%, 17/39), 1p (41.0%, 16/39), 2q (38.5%, 15/39), 9q (35.9%, 14/39), 13p (35.9%, 14/39), 16p (35.9%, 14/39) ,6p (33.3%, 13/39), and 6q (30.7%, 12/39), with minimal deleted regions (MDR) at 3p14.2-21.2 (51.3%, 20/39), 5q15-22 (51.3%, 20/39), 13q14.2-21.2 (48.7%, 19/39), 8p21.1-22 (43.6%, 17/39), 2q32 (35.9%, 14/39), and 16p12-13.1 (33.3%, 13/39). Amplification rates of chromosomal arms 3q, and 8q in smoking LSCC patients were significantly higher than those in non-smoking LSCC patients (P=0.002,P=0.031). While high incidences of gains at chromosomal arms 5p and 12p, and of losses at chromosomal arms 3p, 4q, and 5q were the common feature of chromosomal changes of smoking and non-smoking LSCC patients. CONCLUSION: 3q, 5p, 1q, 8q, 12p, 2p, 18p gains and 3p, 5q, 13q, 8p, 4p, 4q, 1p, 2q, 9q, 13p,16p, 6p, 6q loses might be involved in tumorigenesis and/or progression of LSCC, smoking-induced lung cancer may be associated with 3q, 8q gains.

Dual fluorescence in situ hybridization in detection of HER-2 oncogene amplification in primary hepatocellular carcinoma.

BACKGROUND: Molecular cytogenetics of oncogene HER-2 amplification in primary hepatocellular carcinoma (HCC) is still unknown. The aim of this study was to investigate the frequency of HER-2 oncogene amplification in primary HCC and its relations to clinicopathological parameters and prognosis. METHODS: Forty-two surgical samples from patients with primary HCC were detected for their HER-2 oncogene amplification. The number of chromosome 17 and their ratio were tested by dual fluorescence in situ hybridization (FISH) technique, and then the correlations between HER-2 amplification, clinicopathological characteristics and prognosis were analyzed statistically. RESULTS: HER-2 oncogene amplification was detected in 9 (21.4%) of the 42 primary HCCs, including 4 patients with high copy (HC) (9.5%) and 5 patients with low copy (LC) (11.9%). HER-2 amplification was associated significantly with tumor size and postoperative survival time of HCC patients (P<0.05), and the presence of HER-2 gene amplification was correlated with postoperative relapse (P=0.257), but not related to sex, age, AFP level, HBV infection, histopathological grading and clinical staging of HCC patients (P>0.05). The HER-2 oncogene copy was examined in 31 (73.8%) of the 42 primary HCCs, consisting of 9 patients with HER-2 amplification (21.4%) and 22 patients with aneuploidy (52.4%). No significant relations were observed between the HER-2 oncogene copy, patient sex, tumor size, histopathological grading, clinical staging, postoperative relapse and survival time (P>0.05); but the HER-2 oncogene copy was correlated significantly to age, AFP level and HBV infection (P<0.05). CONCLUSIONS: There are a lower frequency of HER-2 oncogene amplification and a higher frequency of chromosome 17 aneuploidy in primary HCC. HER-2 oncogene amplification may be involved in the development and progression of large HCC in some patients, and seems to be a valuably independent prognostic factor predicting the recurrence and poor survival in patients with large HCC.

[Loss of p53 gene and amplification of HER-2 oncogene in primary hepatocellular carcinoma and their clinical significance].

OBJECTIVE: To investigate the deletion of p53 gene and amplification of HER-2 oncogene at chromosome 17 in primary hepatocellular carcinoma (HCC) and the clinical significance. METHODS: Interphase dual fluorescence in situ hybridization (FISH) was applied to detect the ratio of the number of p53 gene copy or HER-2 oncogene copy to that of chromosome 17 copy, to determine the p53 gene deletion and HER-2 oncogene amplification in nuclei prepared from 42 surgical specimens of HCC. Statistical analysis for their clinical significance was performed. RESULTS: Loss of p53 gene and amplification of HER-2 oncogene were detected in 27 (64.3%) and 9 (21.4%) of the 42 HCC respectively including 4 cases with low and 5 with high copy amplification. Six (14.3%) of 42 HCC showed simultaneously p53 gene deletion and HER-2 oncogene amplification. 61.9% (26/42) of HCC were polysomy 17, which correlated positively with p53 gene deletion (chi(2) = 12.286, P < 0.001). No close correlation between p53 gene loss and HER-2 oncogene amplification was found (chi(2) = 0.00, P = 1.00). Loss of p53 gene was related to the serum alpha-fetoprotein (AFP) level and the tumor size (P < 0.05). The postoperative 2-year survival rate (18.5%) of HCC patients with p53 gene deletion was significantly lower than postoperative 2-year survival rate (60.0%) of those without p53 gene loss (chi(2) = 7.467, P = 0.006). Meanwhile, HER-2 oncogene amplification showed a tendency of correlation with the tumor size (chi(2) = 2.973, P = 0.085), and the postoperative 2-year survival rate (0/9) of HCC patients with HER-2 oncogene amplification was significantly lower than those (42.4%) without HER-2 oncogene amplification (chi(2) = 3.977, P = 0.046). CONCLUSION: There were a high frequency of p53 gene deletion and a low frequency of HER-2 oncogene amplification in primary HCC, which might be involved in initiation and development of a subset of primary HCC.

Evidence for another tumor suppressor gene at 17p13.3 distal to TP53 in hepatocellular carcinoma.

Loss of 17p is one of the most frequent chromosomal alterations in primary hepatocellular carcinoma (HCC). In the present study, the association between loss of 17p and TP53 mutation was analyzed in 94 primary HCC of Chinese patients. Loss of one allele at 17p13.3 distal to the TP53 gene was observed in 48 of 94 HCC (51%), whereas loss of heterozygosity (LOH) at 17p13.1 near the TP53 gene was detected in 30 of 94 HCC (32%) and TP53 mutation was detected in only 22 of 94 HCC (23%). High frequency of LOH at 17p13.3 and relatively low frequency of TP53 mutation in the present study indicate that loss of function of a putative tumor suppressor gene at 17p13.3 may play a more important role than TP53 in HCC development.

[Differentially expressed gene in nasopharyngeal carcinoma cell lines with various metastatic potentialities].

OBJECTIVE: To investigate gene expression profile in nasopharyngeaL carcinoma (NPC) cell lines with different metastatic potentialities, in order to identify new candidate genes related to the development, progress and metastasis of NPC. METHODS: The mRNA expressions of high metastatic NPC cell line 5-8F, tumorigenic but nonmetastatic NPC cell line 6-10B and non-tumorigenic NPC cell line 13-9B (3 sublines of SUNE-1) were investigated by cDNA microarray containing 14 000 cDNA clones. The alterations in gene expression levels were confirmed by reverse-transcription PCR. RESULTS: There were 82 differentially expressed genes comparing 5-8F and 13-9B; 38 differentially expressed genes comparing 6-10B and 13-9B; 54 comparing 5-8F and 6-10B. There were 12 common differentially expressed genes comparing 6-10B, 5-8F and 13-9B; 14 common differentially expressed genes comparing 5-8F and 13-9B, 6-10B. The expressions of the above genes were involved in metabolism, transcription, differentiation, apoptosis and signal transduction. CONCLUSION: The gene expression profile in nasopharyngeal carcinoma cell lines is an important index in the search of new candidate genes related to NPC.