PRKACA and fibrolamellar hepatocellular carcinoma: Figure 2 shows an example of typical fibrolamellar carcinoma, its immunophenotype and PRKACA FISH result. The most common rearrangement pattern showed a separate green signal with an intact yellow signal per nucleus, followed by two green signals and two intact yellow signals per nucleus. These patterns were seen in 100 of 102 (98%) cases. In the remaining two cases there were unusual signal patterns that were still consistent with PRKACA rearrangement, but also showed additional FISH abnormalities.