Expression of MAGE and GAGE genes in the bronchogenic cancer tissues obtained by bronchoscopy

Jung, Maan Hong; Kim, Ji Ho; Kim, Ji Hae; Park, Ki Ryong; Oak, Chul Ho; Cho, Hyun Myung; Jang, Tae Won

Abstract

BACKGROUND
There has been significant progress in the identification of tumor associated antigens. Among the tumor associated antigens, MAGE (melanoma antigen), BAGE, GAGE, PRAME, NY-ESO were named as cancer/testis specific antigens since they are only expressed in the testis or cancer cells. Because of their relative specificity, they have been considered as the appropriate targets for the specific immunotherapy, or the early diagnosis of several cancers. In bronchogenic cancer, these antigens would be useful as a promising candidate in the screening test or immunotherapy. This study was to investigate the expression of MAGE and GAGE genes in the bronchogenic cancer tissues obtained by bronchoscopy.
METHODS
In five normal bronchial and 26 cancer tissues obtained by bronchoscopic biopsy from 26 bronchogenic cancer patients, total cellular mRNA was extracted. Then RT PCR was run in 35 cycles, with two different kinds of primers designed to detect the several subtypes of MAGE DNA simultaneously and the similar process to detect GAGE DNA was also done. Concurrently, DNA sequencing of the isolates was done in portion to prove the isolates are cloned MAGE and GAGE DNA. With probes confirmed by DNA sequencing, the isolates were reevaluated by Southern blotting. Then the expression of MAGE or GAGE in the bronchogenic cancer tissues was evaluated by the tissue types and clinical staging.
RESULTS
In the five controls, MAGE or GAGE was not detected in any specimen and beta actin was not expressed in 4 cases, suggesting the specimen might be too small to detect beta actin by 35 cycles of PCR. In the 26 cancer tissues, the expression rate of MAGE and GAGE was 42.3% (11/26) and 42.3% (11/26) respectively and MAGE or GAGE were expressed in 17 cases (65.3%). Neither clinical staging nor tissue types were associated with the expression of MAGE or GAGE. Beta actin was not detected in 11 cases of cancer specimen, but MAGE or GAGE were expressed in 10 cases of them.
CONCLUSION
Using these primers in detection of MAGE or GAGE genes in the bronchoscopicbiopsy tissues seems to be effective or complimentary method in screening of bronchogenic cancer patients, who would be the candidate for the possible immunotherapy.