THE IMPACT OF FISH ON OUR UNDERSTANDING OF TESTICULAR-TUMOR DEVELOPMENT

The fusion of techniques of classical cytogenetics and molecular biolo gy has led to the establishment of the fluorescence in situ hybridizat ion (FISH) technique. This method, allowing detailed chromosomal inves tigations in metaphase spreads as well as in interphase nuclei, has en abled pathologists to detect molecular changes in precancerous lesions such as carcinoma in situ of the testis. In particular, its applicati on to paraffin material has allowed the correlation of chromosomal abe rrations with morphological and immunohistochemical characteristics. T hus, recurrent chromosomal aberrations found in invasive testicular tu mours, such as the occurrence of an isochromosome i(12p), are already present in preinvasive stages, indicating an early event in carcinogen esis. Recent work, published in this issue, presents the diagnostic an d prognostic impact of these investigations. (C) 1998 John Wiley & Son s, Ltd.