s. Objectives.  KL‐6 is a specific marker in patients with interstitial lung diseases (ILDs); however, the relationship between elevated levels of KL‐6 and subsequent mortality is not well defined. To determine if elevated serum levels of KL‐6 are associated with increased mortality, and to identify the most suitable cut‐off level of KL‐6 by which to distinguish between good prognosis and poor prognosis, we evaluated the prognostic significance of serum KL‐6 levels in patients with stable‐state ILDs. Methods.  Two hundred and nineteen patients diagnosed with ILDs (152 with idiopathic interstitial pneumonia and 67 with collagen disease‐associated pulmonary fibrosis) at Tsukuba University Hospital from April 1999 to October 2005 were entered in this study. Serum KL‐6 levels in patients with ILDs were measured with a commercially available enzyme immunoassay kit, and these patients were then followed up. Results.  During the follow‐up period, 58 of the 219 patients died of respiratory failure. Patients who died during this period had higher levels of KL‐6 than did those who did not (P = 0.0004). The receiver operating characteristic curve analysis showed 1000 U mL−1 as the most suitable cut‐off level by which to distinguish between the two groups of patients. The 95% specificity serum KL‐6 level with poor outcome was 2750 U mL−1. In univariate and multivariate analysis, elevated serum KL‐6 (>1000 U mL−1) in the stable state indicated poor prognosis (P = 0.0005, log‐rank test; P = 0.0001, Cox proportional hazard model). Conclusions.  Elevated KL‐6 level may provide simple, yet valuable information by which to identify patients with ILDs who are at increased risk for subsequent mortality.

Myofibroblasts have been thought to participate in subepithelial fibrosis in asthma, but the mechanism of myofibroblast induction has not been fully understood. In this study we investigated injury-related myofibroblast induction in a coculture system of guinea-pig epithelial cells and fibroblasts cocultured in a human amnion chamber. After pseudostratified epithelial cells were mechanically scraped, migrated flat epithelial cells differentiated into cuboidal appearances on Day 4 and then returned to their original shapes on Day 8. During the course of the epithelial redifferentiation, it was found by Northern blot analysis, immunohistochemistry for alpha-smooth muscle actin, and electron microscopic observation that the myofibroblasts were transiently induced on Day 4. The myofibroblast induction was inhibited by the blocking of transforming growth factor (TGF)-beta1 and thrombospondin (TSP)-1, indicating that the activation of TGF-beta1 by TSP-1 would induce myofibroblasts. This finding was also supported by a transient upregulation of TSP immunoreactivity and TSP-1 messenger RNA (mRNA) in fibroblasts. Interestingly, epithelial injury reduced TGF-beta1 immunoreactivity in the amnion membrane but did not affect TGF-beta1 mRNA in epithelial cells and fibroblasts, indicating that TGF-beta1 supplied from the extracellular matrix can participate in myofibroblast induction. Concurrently with myofibroblast induction, procollagen type I and III mRNAs were upregulated in fibroblasts, and obvious collagen deposition was observed ultrastructurally around the myofibroblasts compared with the fibroblasts. These results indicate that induced myofibroblasts can be functionally more active in producing collagen than are resting fibroblasts. The present study suggests that epithelial injury stimulates TGF-beta1 release from the extracellular matrix and its activation via TSP-1 production, causing collagen synthesis through myofibroblast induction.

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CA19-9 is a specific tumor marker in patients with gastrointestinal cancer; however, some patients with respiratory disease can have elevated serum levels of CA19-9 as well. In this study we evaluated serum CA19-9 levels of patients with nonmalignant respiratory diseases. We also estimated the prognostic significance of elevated serum levels of CA19-9 in patients with interstitial lung diseases. The study included 554 patients who had been diagnosed at our hospital during the period of 1984-2005. Serum CA19-9 levels in these patients were measured with a commercially available kit. Elevated levels (>37 U/mL) of CA19-9 were observed in 30.7% of patients with lung cancer. Furthermore, 38.9% of patients with idiopathic interstitial pneumonia (IIP), collagen disease-associated pulmonary fibrosis (CDPF), diffuse panbronchiolitis (DPB), and bronchiectasis had elevated serum CA19-9 levels. Survival rates were significantly lower in patients with interstitial lung diseases (IIP and CDPF) and elevated serum CA19-9 levels than in those with levels in the normal range (P=0.0065). Serum CA19-9 was elevated in some patients with nonmalignant diffuse lung diseases. Therefore, clinicians should pay attention to the evidence that increased serum CA19-9 levels can be found in nonmalignant respiratory disease patients. In patients with IIP and CDPF, elevated serum CA19-9 levels may be related to poor prognosis.

In order to evaluate clinicopathological features associated with liver metastases from lung cancer, we reviewed our experience of lung cancer patients seen in our division. Of the 1073 lung cancer patients diagnosed between October 1976 and May 2002, 62 (5.8%) patients had liver metastasis. The incidence of liver metastasis was 17.5% in small-cell lung cancer (SCLC) patients, whereas the incidence in non-small-cell lung cancer patients was 3.8%. Of the 62 patients, 17 had sole liver metastasis, and the remaining 45 had synchronous spread to the liver and one or more other organs. Six of 12 squamous cell carcinoma patients and 10 of 28 SCLC patients had sole liver metastasis. However, 19 of 20 adenocarcinoma patients showed liver metastasis with one or more other organs. In morphological liver metastasis, 26 of the 28 SCLC patients had multiple nodules, whereas 16 of the 34 non-small-cell lung cancer patients had a solitary liver nodule (p = 0.0006). Liver is a possible site of extrathoracic spread of disease for some patients with lung cancer, especially with SCLC. When the histological types are squamous cell carcinoma or SCLC, it would also be considered likely that an isolated liver mass represents a metastasis even though there is no metastatic disease elsewhere.