Figure 3

Telomere FISH. Telomere-specific FISH demonstrating ALT-positive and ALT-negative tumors. (a) Representative example of a chromophobe hepatocellular carcinoma with abrupt anaplasia demonstrating the ALT phenotype. The arrows indicate the distinctive large, ultrabright, intranuclear foci of telomere FISH signals that mark the ALT-associated telomeric foci. (b) Representative example of an ALT-negative hepatocellular carcinoma with typical morphology. This tumor lacks the morphology of chromophobe hepatocellular carcinoma with abrupt anaplasia. The asterisks indicate robust telomere signals present in the tumor cells. Original magnification × 400. Because the telomere signals in the ALT-positive case quickly become saturated, the cy3 exposure time in a was 200 ms, whereas in b, it was 600 ms.