They consistently show a specific t(X;18;p11;q11), which usually represents either of two gene fusions, SYT-SSX1 or SYT-SSX2, encoding putative transcriptional proteins differing at 13 amino acid positions.     ///    "Among other comparisons, there was a strong association of fusion type and morphology (P < 0.001), with almost all of the SYT-SSX2 tumors showing absence of glandular differentiation (monophasic histology) and almost all of the biphasic tumors containing SYT-SSX1. "    ///    "Within the subset of patients with localized disease at diagnosis (n = 202), the median and 5-year survival for the SYT-SSX1 and the SYT-SSX2 groups were 9.2 years and 61% versus 13.7 years and 77%, respectively. "    ///    "Median and 5-year overall survivals for the SYT-SSX1 and SYT-SSX2 groups were 6.1 years and 53%, and 13.7 years and 73%, respectively. "    ///    "Overall survival was significantly better among SYT-SSX2 cases (P = 0.03), among cases localized at diagnosis (P < 0.0001), and among patients with primary tumors < 5 cm in greatest dimension (P = 0.01). "    ///    "specifically, the male:female ratio of SYT-SSX1 cases was 1:1, whereas for SYT-SSX2 cases, it was close to 1:2. "    ///    "Previous studies have suggested that patients with SYT-SSX2 tumors do better than those with SYT-SSX1 tumors, but the study groups were too limited to be conclusive. "    ///    "SYT-SSX1 and SYT-SSX2 fusions were detected in 147 tumors (61%) and 91 tumors (37%), respectively. "    ///    "Patients whose tumors contained the SYT-SSX2 fusion (P = 0.08) or were smaller (P = 0.12) showed a trend toward better survival by log-rank test, whereas tumor histology had no impact (P = 0.8). "