Dicer and Drosha in Ovarian Cancer

To the Editor: Merritt et al. (Dec. 18 issue)¹ report finding a relation between prognosis and the expression of Dicer and Drosha in women with ovarian carcinoma of unstated histologic subtype. The histologically defined subtypes of ovarian carcinoma (high-grade serous, clear cell, endometrioid, mucinous, and low-grade serous) are distinct diseases that can be reproducibly diagnosed² and that vary with respect to characteristics of the precursor lesions, the genetic events during oncogenesis,³ outcome,^2,4 and response to chemotherapy.⁴ These subtypes have distinct biomarker-expression profiles.⁵ In cohorts of patients with ovarian carcinoma consisting of a mixture of subtypes, biomarkers preferentially expressed by . . .