Hrad17 expression in thymoma.
OBJECTIVE
We used palindromic polymerase chain reaction-driven complementary deoxyribonucleic acid differential display to identify and isolate a gene, the human homolog of the Schizosaccharomyces pombe checkpoint gene rad17 (Hrad17), from colon cancer tissue. The loss of checkpoint control in mammalian cells results in genomic instability, leading to the amplification, rearrangement, or loss of chromosomes--events associated with tumor progression. We hypothesized that the Hrad17 may be expressed in thymoma, especially in invasive thymoma. We attempted to determine the influence of Hrad17 expression on clinicopathological features for patients with thymoma who had undergone surgery.


METHODS
Expression of Hrad17 messenger ribonucleic acid (RNA) was evaluated by reverse transcription-polymerase chain reaction using a LightCycler in 38 thymomas and 10 adjacent histologically normal thymus samples from patients for whom follow-up data was available.


RESULTS
Hrad17 transcripts were detected in all 38 tumor samples (8.789 +/- 7.337) at levels significantly higher than those in normal thymus samples (1.908 +/- 2.267, p < 0.0001). No relationship was seen between Hrad17 gene expression and age, gender, or pathological thymoma subtypes. Hrad17 mRNA expression in invasive thymomas (stage II-IV, 10.067 +/- 5.293) was significantly higher than that in stage I thymomas (5.193 +/- 4.485, p = 0.0168). Immunohistochemistry showed that Hrad17 protein was highly expressed in invasive thymoma tumor tissue but not within the normal thymus tissue.


CONCLUSIONS
Hrad17 was highly expressed in invasive thymoma.
Sasaki
Hidefumi
H
Department of Surgery II, Nagoya City University Medical School, Nagoya, Japan.
Kobayashi
Yoshihiro
Y
Yukiue
Haruhiro
H
Yano
Motoki
M
Kaji
Masahiro
M
Fukai
Ichiro
I
Kiriyama
Masanobu
M
Yamakawa
Yosuke
Y
Fujii
Yoshitaka
Y
D018797:Cell Cycle Proteins / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D013945:Thymoma / Q000235:genetics*; D013953:Thymus Neoplasms / Q000235:genetics*
D018797:Cell Cycle Proteins; D012333:RNA, Messenger; C113575:Rad17 protein, human