Pulmonary nodules resected at video-assisted thoracoscopic surgery: etiology in 426 patients.

PURPOSE: To determine the etiology of pulmonary nodules resected at video-assisted thoracoscopic surgery (VATS) and establish the probabilities that single or multiple nodules resected at VATS represent malignancy in patients with or patients without known cancer. MATERIALS AND METHODS: Pathology reports from VATS performed between January 1995 and July 1997 were searched for data on gross specimens revealing pulmonary nodules 3 cm or smaller. Findings were correlated with clinical and histologic data. RESULTS: In 254 patients with one nodule resected at VATS, the nodules were malignant in 108 patients with and in 32 patients without known cancer (P < .03). Among 172 patients with multiple nodules resected, at least one nodule was malignant in 85 patients with and in 20 patients without known cancer (P > .05). Nodules larger than 1 cm were more likely to be malignant than were smaller nodules (P < .002). In patients with known malignancy, nodules smaller than 0.5 cm were more likely to be benign, whereas nodules larger than 0.5 cm but smaller than 1 cm were more likely to be malignant (P < .001). CONCLUSION: A single pulmonary nodule resected at VATS was more likely to be malignant in patients with known cancer. Nodules larger than 1 cm but smaller than 3 cm resected at VATS were more likely to be malignant. Nodules smaller than 0.5 cm were more likely to be benign.

Mutations altering the mitochondrial-cytoplasmic distribution of Mod5p implicate the actin cytoskeleton and mRNA 3' ends and/or protein synthesis in mitochondrial delivery.

The Saccharomyces cerevisiae MOD5 gene encodes proteins that function in three subcellular locations: mitochondria, the cytoplasm, and nuclei (M. Boguta, L.A. Hunter, W.-C. Shen, E. C. Gillman, N. C. Martin, and A. K. Hopper, Mol. Cell. Biol. 14:2298-2306, 1994; E. C. Gillman, L. B. Slusher, N. C. Martin, and A. K. Hopper, Mol. Cell. Biol. 11:2382-2390, 1991). A mutant allele of MOD5 encoding a protein (Mod5p-I,KR6) located predominantly in mitochondria was constructed. Mutants defective in delivering Mod5p-I,KR6 to mitochondria were sought by selecting cells with increased cytosolic activity of this protein. Twenty-five mutants defining four complementation groups, mdp1, mdp2, mdp3, and mdp4, were found. They are unable to respire at 34 degrees C or to grow on glucose medium at 38 degrees C. Cell fractionation studies showed that mdp1, mdp2, and mdp3 mutants have an altered mitochondrial-cytoplasmic distribution of Mod5p. mdp2 can be suppressed by ACT1, the actin-encoding gene. The actin cytoskeleton organization is also aberrant in mdp2 cells. MDP2 is the same as VRP1 (S. F. H. Donnelly, M. J. Picklington, D. Pallotta, and E. Orr, Mol. Microbiol. 10:585-596, 1993). MDP3 is identical to PAN1, which encodes a protein that interacts with mRNA 3' ends and affects initiation of protein synthesis (A. B. Sachs and J. A. Deardoff, Cell 70:961-973, 1992). These results implicate the actin cytoskeleton and mRNA 3' ends and/or protein synthesis as being as important for protein distribution in S. cerevisiae as they are for distribution of cytosolic proteins in higher eukaryotes. This provides the potential to apply genetic and molecular approaches to study gene products and mechanisms involved in this type of protein distribution. The selection strategy also offers a new approach for identifying gene products involved in the distribution of proteins to their subscellular destinations.