Cytogenetic and morphologic characteristics of gastrointestinal stromal tumors. Recurrent rearrangement of chromosome 1 and losses of chromosomes 14 and 22 as common anomalies.

We present cytogenetic findings in five gastrointestinal stromal tumors (GISTs). Three of these five cases had abnormal karyotypes with clonal chromosomal aberrations. The most common karyotypic pattern was a combined loss of chromosomes 14 and 22 in a total of three cases. Among these cases, additional recurrent chromosomal abnormalities were loss of 1p and/or 9, detected in two cases each. Another karyotypic feature consisted of polyploidisation, leading to hypotetraploid chromosome numbers in one case. These cytogenetic results provide evidence for a characteristic karyotypic pattern consisting of -14 and -22 in a subset of GISTs.