Our aim is to examine the impact of DICER1 mutations on the pathogenesis of pleuropulmonary blastoma (PPB) by evaluating the mutation frequency and investigating the family history of Chinese patients with PPB.The family histories of 12 children with PPB recruited consecutively were surveyed.Blood samples from patients and their first-degree relatives were tested for DICER1 mutations.Whole-genome sequencing of blood samples and formalin-fixed and paraffin-embedded (FFPE) tumor tissue was performed in one family with twins.Twelve patients with PPB included six type Ⅱ and six type Ⅲ cases.Seven of the 12 patients harbored DICER1 mutations,six of which were frameshift or nonsense mutations.Another case carried a germline DICER1 mutation affecting the splice site.FFPE sample had a nonsense mutation in TDG and missense mutations in DICER1.In addition,two cases with DICER1 mutations were found to have lung cysts preceding the diagnosis of PPB.Furthermore,one patient had a family history remarkable for thyroid diseases.Our results indicate that the germline mutation frequency in Chinese patients with PPB is similar to the ones reported for patients from USA,UK,and Japan.Moreover,our study strongly suggests that investigating the family history and detecting germline DICER1 mutations might be of benefit to increasing awareness and improving the accuracy of the differential diagnosis of PPB from non-malignant lung cysts.