Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto City, Kumamoto, Japan.
J Surg Oncol. 2013 Mar;107(4):402-7. doi: 10.1002/jso.23225. Epub 2012 Aug 23.
The destruction of the basement membrane (BM) is the first step in cancer invasion and metastasis. Type IV collagen is a major component of the BM, and is composed of six genetically distinct α(IV) chains; α1(IV) to α6(IV). The loss of α5(IV) and α6(IV) chains from the epithelial BM at the early stage of cancer invasion has been reported in several types of cancers. However, the expression of α5(IV) and α6(IV) chains in extrahepatic bile duct carcinoma (EBDC) remains unclear.
We examined the expression of α(IV) chains by immunohistochemistry using 71 resected EBDC specimens. Prognostic significance of α(IV) chains was examined by Cox regression and Kaplan-Meier analyses.
In the invasive cancer, the expression of α6(IV) chain in the BM was lost partially or completely preceded by the loss of α2(IV) chain. The loss of α6(IV) chain in the BM of the invasive cancer was related to the tumor classification, TNM stages, and the expression of α2(IV) chain. The patients with α2(IV)-negative and α6(IV)-negative chains had significantly poorer prognosis than those with α2(IV)-positive and α6(IV)-positive/negative chains (P = 0.04).
The loss of α2(IV) and α6(IV) chains might be a useful prognostic factor in patients with EBDC.
基底膜（BM）的破坏是癌症侵袭和转移的第一步。IV 型胶原是 BM 的主要成分，由六个遗传上不同的α（IV）链组成；α1（IV）到α6（IV）。在几种癌症的早期侵袭阶段，上皮 BM 中α5（IV）和α6（IV）链的丢失已有报道。然而，α5（IV）和α6（IV）链在肝外胆管癌（EBDC）中的表达仍不清楚。
我们使用 71 例切除的 EBDC 标本通过免疫组织化学检查α（IV）链的表达。使用 Cox 回归和 Kaplan-Meier 分析检查α（IV）链的预后意义。
在侵袭性癌症中，α6（IV）链在 BM 中的表达缺失部分或完全先于α2（IV）链的缺失。BM 中α6（IV）链的缺失与肿瘤分类、TNM 分期和α2（IV）链的表达有关。α2（IV）阴性和α6（IV）阴性链的患者预后明显比α2（IV）阳性和α6（IV）阳性/阴性链的患者差（P=0.04）。
α2（IV）和α6（IV）链的缺失可能是 EBDC 患者的一个有用的预后因素。
