Previously, we reported gene amplification at chromosome 3q26-27 in more than one third of squamous cell carcinomas of the lung. Frequent amplification of eukaryotic translation initiation factor 4G on 3q27.1 indicated a possible role of this amplification in translation initiation. The analysis of 61 squamous cell lung carcinomas shows that the percentage of carcinomas with a 3q27.1 amplification increases in higher malignant tumors. Non-invasive (T1) and minimal-invasive (T2) tumor stages showed similar percentages of amplified and non-amplified tumors, whereas locallyinvasive (T3) tumors revealed a statistically significant (p < 0.05) increased percentage of amplified tumors. Microarrays were used to analyze the expression pattern of genes mapping in the amplified domain and its flanking regions (3q25-28) as well as the expression of genes directly or indirectly associated with translation initiation in squamous cell carcinoma, large cell carcinoma, adenocarcinoma and small cell carcinoma. Three genes, namely FXR1, CLAPM1 and EIF4G, are most frequently overexpressed in the center of the amplified domain in squamous cell carcinomas. The eukaryotic translation initiation factors 4A1, 2B and 4B as well as the poly(A)-binding protein PABPC1 where found to be overexpressed in all lung cancer entities. We found, however, no overexpression of eIF4E. Our results contribute to the understanding of the frequent amplification processes in squamous cell carcinomas of the lung and to the understanding of the translation initiation that appears not to require eIF4E in lung carcinogenesis. ' 2007 Wiley-Liss, Inc.

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eIF4G-1 belongs to the family of translational initiation factors and is recognized as the central organizing protein in recruitment of mRNA during translational initiation. Previously published studies have provided some evidence that overexpression of translational factors is a general event in the process of carcinogenesis. We have characterized the expression of the eIF4G-1 protein in 33 squamous cell carcinoma (SCC) of the lung by Western blotting. Overexpression of the eIF4G-1 protein was detected in 61% of the tumors compared to the respective normal lung tissue. In addition, we analyzed the expression of this protein by immunohistochemistry in 138 SCC of the lung using a newly generated antibody that is specific for eIF4G-1 as determined by Western blotting. This anti-eIF4G-1 antibody was suitable for the immunohistochemistry of paraffin-embedded tissues. There is a strong cytoplasmic staining detected in the tumor areas that is consistent with the cytoplasmic localization of the translation factor eIF4G-1. In 72% of the examined tissue sections of SCCs of the lung, we detected an overexpression of the eIF4G-1 protein compared to the surrounding connective tissue. Two tumors that were analyzed by both methods showed an overexpression of eIF4G-1 both with Western blot analysis and immunohistochemical staining. Overexpression of eIF4G-1 may result in an increased amount of the translation initiation complex eIF4F, which in turn may activate the translation of the same target mRNAs as eIF4E. © 2002 Wiley-Liss, Inc. Key words: eIF4G; expression; squamous cell lung carcinomaTranslational initiation factors are involved in mRNA recruitment to the 43S initiation complex. A variety of previously published studies have shown that translational initiaton factors, in particularly the cap-binding protein eIF4E, are involved in the process of carcinogenesis. Overexpression of eIF4E resulted in cell transformation as shown for NIH3T3, CHO or REF. A transformed phenotype can include morphologic changes or shortening of generation time. 1 It is additionally described that eIF4E is overexpressed in different tumor types. The highest eIF4E elevation was found in breast cancer as demonstrated by an overexpression of this protein using Western blot analysis and immunohistochemical staining techniques. 2 Also in colon carcinomas and in head and neck squamous cell carcinomas, an elevated eIF4E expression was detected. 1,3 Further studies have shown that there is an increased expression of the initiation factors 4E and 2alpha in lymphomas and a correlation to the biologic aggressiveness. 4 Other members belonging to the family of translational initiation factors include eIF3, eIF4A and eIF4G. There are 2 isoforms of eIF4G in mammals: eIF4G-1 and eIF4G-2. The molecular masses range from 154 kDa to 220 kDa and have 46% identity at the amino acid level. 5-8 The eIF4G-1 translational factor forms with 2 other factors, termed eIF4E and eIF4A, a large protein complex called eIF4F. eIF4G-1 has binding sites for these 2 factors, for t...

There is very limited knowledge about the antibody response against tumor-expressed antigens in lung cancer. To arrive at a more complete picture of lung cancer antigens, we generated 2 cDNA libraries from squamous cell lung carcinoma and isolated 15 immunogenic antigens using autologous sera. Among the antigens most frequently identified were the lymphoid blast crisis oncogene (LBC), an unknown hypothetical protein and the p53-binding protein (TP53 BP), which have already been associated with tumor development. Of the immunogenic antigens, 6 map to chromosomes that are frequently altered in squamous cell lung carcinoma. SEREX database analysis showed that 7 of the identified immunogenic antigens have been associated with the humoral immune response in other human tumors. Screening with heterologous sera of patients with lung carcinoma identified 4 antigens, including human protein kinase C and TP53 BP, which have also been found by autologous screening. Only 1 of the 15 identified antigens reacted with any of the 36 control sera, which were taken from individuals without known disease. Sera from adenocarcinoma and large cell carcinoma of the lung were not reactive for the antigens. In summary, using 2 newly established cDNA libraries, we isolated 15 novel antigens, which were subsequently evaluated for the frequency of their corresponding antibodies in autologous, normal and heterologous sera; their chromosomal localization; and their correlation with survival after surgery. © 2002 Wiley-Liss, Inc. Key words: lung cancer; SEREX; autologous sera; heterologous seraThere is mounting evidence that many tumors express antigens that elicit an immune response in cancer patients. Target antigens of tumor-related autoantibodies can be oncoproteins, tumor-suppressor proteins or proliferation-associated antigens. 1 The most prominent example of an autoimmune response against a tumorassociated protein is the antibody response against the tumorsuppressor TP53. Examples of TP53-directed antibodies in cancer patients include antibodies in 50% of bladder cancer patients, in 12% of B-cell lymphoma patients, in 23% of ovarian cancer patients, in 32% of colon cancer patients and in 42% of breast cancer patients. [2][3][4][5][6] In addition, there is an increasing number of other tumor or proliferation-associated gene products that cause an antibody response, including, e.g., c-myb with an antibody response in 43% of breast cancer patients and cyclin B1 in 15% of hepatocellular carcinoma patients. 7,8 There are limited data on the autoantibody response in human lung cancer patients, specifically patients suffering from squamous cell lung carcinoma, which constitutes 40 -50% of lung cancer patients. Lung cancer is the most frequent lethal tumor in Western societies, with a 5-year survival rate of approximately 13%. 9 The most frequent autoantibodies in lung cancer patients are directed against TP53, with an antibody response detected in 14.3% of lung cancer patients and 21% of small cell lung cancer patients, and against L-myc and ...