Nuclear
beta-catenin staining in
soft tissue sarcomas (STSs) has been shown to correlate with
tumor progression as assessed by proliferative activity or poor prognosis. Frequent activation of Wnt signaling pathway has been also shown in
synovial sarcoma (SS), suggesting a specific role of this pathway in SS. We examined roles of nuclear
beta-catenin staining within
soft tissue sarcomas. Immunohistochemical detection of nuclear
beta-catenin accumulation correlated with
cyclin D1 overexpression in spindle cell and pleomorphic
sarcomas (P = .037), and the expression of these
proteins evenly distributed throughout each section. In some cases, strong
beta-catenin nuclear staining was observed in highly pleomorphic and mitotic cells. Furthermore,
tumors with nuclear
beta-catenin accumulation showed statistically significant increasing
cyclin D1 mRNA expression level compared with those without (P = .023).
Cyclin D1 mRNA expression levels were statistically higher in
tumors with
cyclin D1 overexpression than in
tumors without (P = .037), suggesting that
cyclin D1 overexpression is due to transcriptional activation. However, these correlations could not be detected in SS. In biphasic SS,
beta-catenin nuclear staining was observed in spindle cells, whereas
cyclin D1 nuclear staining was seen in glandular areas where
beta-catenin kept membranous expression. Mutations in exon 3 of the
beta-catenin gene and in the mutation cluster region of
adenomatous polyposis coli gene were absent in this series of cases. Thus,
cyclin D1 could be considered as one of the targets of the nuclear
beta-catenin in spindle cell and pleomorphic
sarcomas. A possible association between
beta-catenin accumulation and spindle cell morphogenesis may exist in SS.