The studies by Fiegl, Kircher, and Zojer are impressive and clinically important. Thus, they have extended the use of FISH1 to distinguish neoplastic from reactive normal cells in effusions, lymph nodes, and metastases. They have emphasized the potential of performing FISH on both the primary tumor and resultant metastases to prove common clonality. Taken together with our studies, a strong case for expanded use of FISH in clinical settings has been established.

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The abbreviation used is: FISH, fluorescence in situ hybridization.