Biological significance of fatty acid binding protein in human gastric and colonic carcinoma

1.肝型脂肪酸结合蛋白（L-FABP）在胃癌（n=667）和肺癌（n=199）中的表达频率分别为38%和60%。L-FABP的表达与脂肪酸合成酶（FAS）的表达、临床病理因素及患者生存期无关。肺癌组织中L-FABP的表达与血管内皮生长因子的表达密切相关，提示L-FABP可能参与了脂肪酸的摄取.心脏型（H-）FABP在胃癌中的表达率为19%，其表达与FAS表达、淋巴结转移、肝转移等临床病理因素及患者生存期密切相关。由此可见，H-FABP可能参与FAS合成脂肪酸的细胞内代谢途径。L-FABP在正常胃粘膜中不表达，在化生上皮中表达率为90%，在腺瘤中表达率为38%。说明L-FABP在胃癌前病变中有表达.与L-FABP相比，H-FABP在正常胃粘膜和癌前胃粘膜（化生和腺瘤）中均未见表达. L-FABP和H-FABP在结肠癌中的表达正在研究中. 4株结肠癌细胞和8株胃癌细胞中有6株产生H-FABP，而12株胃癌细胞中只有TKGW细胞产生L-FABP.通过双向电泳和Western blotting，正常肝L-FABP中形成3个斑点，而从TKGW细胞中提取的L-FABP中观察到4个斑点，除了肝L-FABP中的斑点外还增加了一个斑点.棕榈酸酯（1.9 × 10 ~（13）<-4>~ 7.5 × 10 ~（13）<-4>mol/L）处理胃癌细胞和结肠癌细胞后，癌细胞形态无明显改变，无脂肪堆积和生长迟缓。

1. Liver-type fatty acid-binding protein (L-FABP) was expressed in gastric carcinoma (n=667) at 38% and lung carcinoma (n=199) at 60% in frequency, respectively. Expression of L-FABP was not associated with that of fatty acid synthase (FAS), clinicopathologic factors and patient survival in these two carcinomas. In lung carcinoma, L-FABP expression showed close association with that of vascular endothelial growth factor, suggesting possible role of L-FABP in fatty acid uptake from blood stream.2. Expression of heart-type (H-) FABP was observed at 19% in frequency in gastric carcinoma, and its expression revealed good correlation with expression of FAS, clinicopathologic factors including lymph node metastasis and hepatic metastasis, and patient survival. From these, H-FABP seems to be involved in intracellular metabolic pathway(s) of fatty acid(s) synthesized by FAS.3. L-FABP was not found in normal gastric epithelium but found at 90% in metaplastic epithelium and 38% in adenoma in frequency. Therefore L-FABP was expressed in precancerous stage of stomach carcinoma.4. In contrast with L-FABP, H-FABP was observed in neither normal nor preneoplastic (metaplasia and adenoma) gastric mucosa.5. Expression of L-FABP and H-FABP in colon carcinoma is now under investigation.6. Four colon cancer cell lines and six out of eight stomach cancer cell lines produced H-FABP, while only TKGW gastric cancer cell line produced L-FABP among 12 cell lines examined.7. By two dimensional gel electrophoresis and western blotting, three spots were formed in normal liver L-FABP, while four spots, one additional spot to those in liver L-FABP, were observed in L-FABP extracted from TKGW cells.8. Treatment with palmitate (1.9x10^<-4>- 7.5x10^<-4> mol/L) of gastric cancer cells and colon cancer cells revealed no remarkable morphological change, fat accumulation and growth retardation of cancer cells.