Fluorescent in situ hybridization (FISH) in the differential diagnosis of ground-glass opacities in the lung

Computed tomographic (CT) screening for lung cancer has increased the detection rate of nodules manifesting as ground-glass opacities (GGOs). The natural history of this new entity it is not well known nor is the factors that influence the growth, progression and malignant potential. This genetic study was performed in order to identify molecular markers with possible diagnostic and prognostic significance to differentiate lesions with malignant or benign profiles. Ten pure GGO fresh samples and 5 specimens of normal lung tissue were cytogenetically investigated using a direct method and short-term cultures, and molecular analysis was performed using the 4-target FISH LAVysion kit for the detection of non-small cell lung cancer (NSCLC). Interestingly, all the karyotypes turned out to be normal both with the direct method and cultured cells, while in 3 out of 10 GGOs FISH analysis was abnormal for all the targets and in 2 cases only c-MYC amplification was observed. Karyotypes and FISH performed on the normal tissue samples gave normal results. Two of three FISH positive patients died, one had a relapse of the disease and at the last follow-up showed lung and bone metastases. Despite the small sample due to the rarity of pure GGOs, these preliminary results indicate that interphase FISH analyses are more informative than metaphase studies and might contribute clinically relevant information about the nature of these lesions.