A micropapillary pattern is predictive of a poor prognosis in lung adenocarcinoma, and reduced surfactant apoprotein A expression in the micropapillary pattern is an excellent indicator of a poor prognosis.

A micropapillary pattern is defined as papillary tufts without a fibrovascular core and is known to be a factor that indicates a poor prognosis in numerous cancers. However, their role in lung adenocarcinoma has not been investigated widely. In 185 cases of small-size lung adenocarcinoma (< or =3 cm), cases with a micropapillary pattern ratio of more than 1% (analyzed by NIH image) were defined as micropapillary pattern positive. Correlations between the micropapillary pattern and clinicopathological factors were investigated and immunohistochemical expression of mucin and various antigens was examined in regions with and without micropapillary patterns. Micropapillary pattern-positive tumors (micropapillary pattern ratio > or =1%) were observed in 11.4% of cases (21/185) and the micropapillary pattern ratio correlated with TNM stage (P=0.0002), lymphatic invasion (P=0.0002) and lymph node metastasis (P=0.03). Disease-free interval (P<0.0002) and survival (P=0.027) were significantly shorter for micropapillary pattern-positive patients, and micropapillary pattern-positive stage IA cases also had a significantly shorter disease-free interval (P<0.0001). MUC1 was expressed strongly across the surface of the micropapillary structure, whereas MUC4 tended to show lower expression in the micropapillary pattern. It was noteworthy that the disease-free interval in patients with high surfactant apoprotein A expression was significantly better than in patients with low surfactant apoprotein A expression (P=0.03), and no recurrence or death occurred in patients with high surfactant apoprotein A expression. Our results show that the micropapillary pattern ratio correlates with lymphatic invasion and lymph node metastasis, and that a high micropapillary pattern ratio leads to a poor prognosis. High MUC1 expression on the surface is an important characteristic of a micropapillary pattern, and reduced surfactant apoprotein A expression in the micropapillary pattern may be an excellent indicator for poor prognosis in small-size lung adenocarcinoma.

MUC4 expression correlates with poor prognosis in small-sized lung adenocarcinoma.

The mortality of lung cancer remains high, despite improved diagnostic techniques that allow small lung tumors to be detected. In this study, we evaluated the prognostic significance of the tracheal mucin MUC4 by immunohistochemical investigation of the expression profiles of MUC4, ErbB2, p27 and MUC1 in lung adenocarcinoma specimens (non-bronchiolo-alveolar type, < or =3cm) from 185 patients. MUC4 is a membrane mucin, similarly to MUC1, and in addition MUC4 functions as an intra-membrane ligand for receptor tyrosine kinase ErbB2 and is associated with regulation of p27. However, MUC4 expression was found to be unrelated to expression of MUC1, ErbB2 and p27 in small-sized lung adenocarcinomas. The disease-free interval (DFI) and survival rate of 25 patients with high MUC4 expression (> or =25% of neoplastic cells stained) were significantly lower than those of 160 patients with low MUC4 expression (<25% of neoplastic cells stained) (P<0.05), whereas ErbB2 and p27 expression showed no significant correlation with DFI and survival. Univariate analysis showed that high MUC4 and p27 expression correlated with blood vessel invasion (P=0.0004), and MUC4 expression was frequently detected in regions of stromal invasion. In addition, the survival rate of stage IA patients with high MUC4 expression was significantly lower than that of stage IA patients with low MUC4 expression (P<0.05). In conclusion, high MUC4 expression in small-sized lung adenocarcinomas correlates with a short DFI and a poor survival rate. Therefore, MUC4 expression might be a new independent factor for prediction of outcome and indication of poor prognosis in lung adenocarcinoma.

Pulmonary dirofilariasis with serologic study on familial infection with Dirofilaria immitis.

An asymptomatic patient with a pulmonary coin lesion surgically diagnosed with pulmonary dirofilariasis caused by infection with Dirofilaria immitis (D. immitis) is presented. The preoperative stored serum of the patient was positive for D. immitis by enzyme-linked immunosorbent assay (ELISA). A family study showed that three of five family members were seropositive for D. immitis. These results suggest that family members of a patient with pulmonary dirofilariasis were frequently exposed to D. immitis and serodiagnostic methods are useful for detecting subclinical infection of D. immitis.