Novel method for rapid identification of micropapillary or solid components in early-stage lung adenocarcinoma.

Objective: Sublobar resection may be insufficient for early-stage lung adenocarcinoma with micropapillary or solid components because of the associated higher incidence of locoregional recurrence. This study sought to establish a novel method for rapidly identifying their presence to facilitate decision making for sublobar resection.

Methods: Antibody arrays of adhesion and apoptosis molecules were applied for adenocarcinomas with or without micropapillary/solid components to identify differentially expressed proteins. A semi-dry dot-blot system that visualizes the presence of target proteins was used to determine the presence of micropapillary or solid components in a prospective cohort of patients with clinical stage I who underwent operation. Sensitivity and specificity were calculated by comparing semi-dry dot-blot results with pathologic examinations.

Results: Insulin-like growth factor-binding protein 2 and P-cadherin were found more frequently in the micropapillary or solid positive group, and these were used as the target proteins in the semi-dry dot-blot system for detection of micropapillary or solid components. A total of 68 nodules with a mean size of 2.3 ± 0.7 cm, including 13 (19.1%) with a micropapillary and 20 (29.4%) with a solid pattern, were recruited. Micropapillary or solid (+) lesions were more likely to have lymph node upstaging, greater diameter, and higher maximum standardized uptake value. The specificity and sensitivity for detecting the minor presence of micropapillary or solid component using the semi-dry dot-blot method were 94.4% (95% confidence interval, 81.3-99.3) and 65.6% (95% confidence interval, 46.8-81.4), respectively. The average test duration was 26.9 ± 2.5 minutes.

Conclusions: Detecting insulin-like growth factor-binding protein 2 and P-cadherin via the semi-dry dot-blot method could identify micropapillary or solid components in early-stage lung adenocarcinoma in a short processing time.