Clinical significance of interleukin-6 (IL-6) in the spread of gastric cancer: role of IL-6 as a prognostic factor.
BACKGROUND
It is becoming clear that various cytokines are associated with the spread of cancer cells. The purpose of this study was to compare interleukin (IL)-6 levels in patients with gastric cancer to elucidate the role of IL-6 in predicting the spread of tumors.


METHODS
In 60 patients, we assessed the correlation of serum IL-6 (pg/ml) with stage, histological findings, hepatic metastasis, and related factors (hepatocyte growth factor [HGF], IL-1beta, tumor necrosis factor [TNF]-alpha, and transforming growth factor [TGF]-beta1). We also investigated the diagnostic significance of the IL-6 level for advanced gastric cancer and lymph node metastasis, as well as the association between IL-6 elevation and outcome. Finally, we examined the expression of IL-6 in tumor tissue.


RESULTS
Significant relationships were seen between serum IL-6 and stage, depth of tumor invasion (pT), lymphatic invasion (ly), venons invasion (v)*, lymph node metastasis (pN), hepatic metastasis (cH), and HGF (P < 0.01; *P < 0.05). With regard to the diagnostic significance of the IL-6 level for advanced gastric cancer and lymph node metastasis, when the cutoff value of IL-6 was set at 1.97 pg/ml, the sensitivity was 81.8% and 87.5%; specificity was 66.7% and 58.3%; and accuracy was 77.1% and 72.9%, respectively. The 1- and 3-year cumulative survival rates for patients with an IL-6 value of more than 1.97 pg/ml (69.0% and 43.4%, respectively) were significantly lower than those for patients with an IL-6 value of 1.97 pg/ml or less (94.4% and 87.2%, respectively; P < 0.05). Immunohistochemical staining was positive for IL-6 in the cytoplasm of cancer cells.


CONCLUSIONS
We suspect that IL-6 is involved in cancer invasion and lymph node and/or hepatic metastasis. Our results indicate that IL-6 could be used as a prognostic factor for survival.
Ashizawa
Tatsuto
T
Department of Digestive Tract Surgery, Hachioji Medical Center of Tokyo Medical University, Tate-machi, Hachioji, Tokyo 193-0998, Japan.
Okada
Ryosuke
R
Suzuki
Yoshiaki
Y
Takagi
Makoto
M
Yamazaki
Tatsuyuki
T
Sumi
Tetsuo
T
Aoki
Toshiaki
T
Ohnuma
Shinobu
S
Aoki
Tatsuya
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood*; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis / Q000097:blood*; D008113:Liver Neoplasms / Q000556:secondary*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D011379:Prognosis; D013274:Stomach Neoplasms / Q000276:immunology* / Q000473:pathology*
D015415:Biomarkers; D014408:Biomarkers, Tumor; D015850:Interleukin-6