A novel cancer testis antigen that is frequently expressed in pancreatic, lung, and endometrial cancers.
OBJECTIVE
To isolate cancer testis antigens that are expressed in pancreatic cancers and may be useful in clinical applications.


METHODS
To efficiently isolate cancer testis antigens, a testis cDNA library was immunoscreened (SEREX) with serum from a patient with pancreatic ductal adenocarcinoma. The expression of isolated antigens in various cancer cell lines and tissues was evaluated by reverse transcription-PCR and Northern blot analyses. The immunogenicity of the antigen in cancer patients was evaluated by detection of the IgG antibody in sera from patients with various cancers.


RESULTS
Of the three clones isolated through screening of a total of 2 x 10(6) cDNA library clones, one clone (KU-CT-1) was found to be expressed in various cancers but only in testis among normal tissues, indicating that it was a novel cancer testis antigen. The KU-CT-1 gene is located on chromosome 10p12 and produces two splice variants, which encode proteins of 397 and 872 amino acids, respectively. KU-CT-1 was expressed in pancreatic cancer tissues (3 of 9, 33%), lung cancer tissues (9 of 24, 38%), and endometrial cancer tissues (7 of 11, 64%). Specific serum IgG antibodies were detected in 3 of 20 pancreatic cancer patients, 2 of 12 endometrial cancer patients, 1 of 18 colon cancer patients, and 1 of 10 prostate cancer patients but not detected in 30 healthy individuals.


CONCLUSIONS
KU-CT-1 is a new cancer testis antigen that is expressed in pancreatic, lung, and endometrial cancers and may be useful for diagnosis and immunotherapy for patients with various cancers.
Okada
Takaho
T
Division of Cellular Signaling, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan.
Akada
Masanori
M
Fujita
Tomonobu
T
Iwata
Takashi
T
Goto
Yasufumi
Y
Kido
Kenji
K
Okada
Tsutomu
T
Matsuzaki
Yuriko
Y
Kobayashi
Kouichi
K
Matsuno
Seiki
S
Sunamura
Makoto
M
Kawakami
Yutaka
Y
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D045744:Cell Line, Tumor; D016889:Endometrial Neoplasms / Q000235:genetics; D005260:Female; D015723:Gene Library; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics; D008297:Male; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics*; D010190:Pancreatic Neoplasms / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013737:Testis / Q000502:physiology
D009363:Neoplasm Proteins