Abstract |
A 75-year-old man was admitted to our hospital because of unconsciousness. His plasma glucose was very low, but his serum levels of insulin and IGF-I were also low. He was found to have a giant solitary pleural tumor, which was completely resected, after which his hypoglycemia ameliorated postoperatively. Histologically, the tumor was consistent with the pathological diagnosis of a solitary fibrous tumor derived from the pleura. Immunohistochemical study revealed positive immunostaining for IGF-II in tumor cells. The presence of high molecular weight (HMW) form of IGF-II in the tumor tissue and patient's serum was confirmed by Western blot analysis. Steady-state mRNA levels of IGF-II and prohormone convertases (PC) 4, a potential protease responsible for IGF-II processing, as determined by RT-PCR were about 14-fold greater and 5-fold less in the tumor tissue than those in normal placental tissue, respectively. Therefore, it is suggested that biologically active, unprocessed HMW form of IGF-II generated from the impaired processing of IGF-II precursor by the defective PC4 expression in the tumor was responsible for the non- islet cell tumor hypoglycemia (NICTH) in the present case.
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Authors | Yuji Tani, Toru Tateno, Hajime Izumiyama, Masaru Doi, Takanobu Yoshimoto, Yukio Hirata |
Journal | Endocrine journal
(Endocr J)
Vol. 55
Issue 5
Pg. 905-11
(Oct 2008)
ISSN: 1348-4540 [Electronic] Japan |
PMID | 18552458
(Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Insulin
- Protein Precursors
- RNA, Messenger
- Insulin-Like Growth Factor II
- PCSK4 protein, human
- Proprotein Convertases
- Subtilisins
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Topics |
- Aged
- Blotting, Western
- Gene Expression
- Humans
- Hypoglycemia
(etiology)
- Immunohistochemistry
- Insulin
(blood)
- Insulin-Like Growth Factor II
(analysis, chemistry, genetics)
- Male
- Molecular Weight
- Proprotein Convertases
(analysis, genetics, metabolism)
- Protein Precursors
(metabolism)
- RNA, Messenger
(analysis)
- Reverse Transcriptase Polymerase Chain Reaction
- Solitary Fibrous Tumor, Pleural
(complications, enzymology, surgery)
- Subtilisins
(analysis, genetics, metabolism)
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