The association between CD34 expression status and the clinicopathological behavior of dedifferentiated liposarcoma.

Lipogenic and fibrous tumors are thought to originate from CD34-positive stromal fibroblastic/fibrocystic cells. Well-differentiated lipogenic tumors typically express CD34, whereas dedifferentiated liposarcoma (DDLPS) often loses it. We conducted survival analyses involving 59 patients with DDLPS. Males comprised 53% of the cohort, and the median age at the time of wide resection of primary DDLPS was 60 years. Loss of CD34 expression was defined as when ≥50% of the dedifferentiated area was immunohistochemically negative for CD34. As a result, 39 of the 59 patients showed loss of CD34 expression during the initial operation for DDLPS. In the univariate analyses, the tumor site in the retroperitoneum/abdominal cavity and loss of CD34 expression were significantly associated with poor overall survival. In the multivariate analyses, loss of CD34 expression (HR = 2.26; 95% CI = 1.02-5.02; p = 0.04) and the tumor site in the retroperitoneum/abdominal cavity (HR = 3.11; 95% CI = 1.09-8.86; p = 0.03) were retained as independent prognostic factors. Six CD34-positive cases lost CD34 expression when they developed metastasis and/or local recurrence, suggesting that the loss was associated with the later stage of the tumor. Therefore, an association existed between the loss of CD34 expression and clinicopathological behaviors such as poorer prognoses and recurrence.