An analysis of blastic plasmacytoid dendritic cell neoplasm with translocations involving the MYC locus identifies t(6;8)(p21;q24) as a recurrent cytogenetic abnormality.

AIMS: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive neoplasm with leukaemic features and frequent skin involvement. Translocations involving the MYC locus have been recently identified as recurrent cytogenetic abnormalities in this entity. The aim of this study was to assess the clinicopathological, immunophenotypic and genetic features in MYC-rearranged BPDCN cases. METHODS AND RESULTS: Pathology archives from six major institutes were queried for cases of BPDCN with 8q24 MYC translocations, and two cases were identified. A literature review identified 14 cases. Clinicopathological features, immunophenotype and cytogenetic and molecular data were reviewed. In these 16 MYC-rearranged cases, the median age at diagnosis was 70.5 years, and there was a male predominance. Whereas all cases showed marrow involvement, skin lesions (62.5%) and lymphadenopathy (50%) were variably seen. The median survival was 11 months. The median percentage of blasts in peripheral blood was 9%. All cases showed expression of CD4, with 10 of 16 being positive for CD56. HLA-DR, CD123, TCL1 and CD303 were positive in all cases tested. Cytogenetic analysis revealed a single recurrent translocation partner of MYC at 6p21 in 11 cases (69%), whereas four cases showed different MYC translocation partners (2p12, Xq24, 3p25, and 14q32). Interestingly, the group of patients with t(6;8)(p21;q24) showed an older median age at diagnosis (74 years) and a remarkably shorter median survival (3 months). CONCLUSIONS: Translocations involving the 8q24 MYC locus more frequently manifest as t(6;8)(p21;q24), and, given its association with specific clinicopathological features suggesting even more aggressive behaviour, t(6;8)(p21;q24) indicate a genetically defined subgroup within BPDCN.

Regional Variability in Percentage of Breast Cancers Reported as Positive for HER2 in California: Implications of Patient Demographics on Laboratory Benchmarks.

OBJECTIVES: The expected regional variability in percent human epidermal growth factor receptor 2 (HER2)-positive breast cancers is not currently clear. METHODS: Data from the 2006 to 2011 California Cancer Registry were examined by county and health service area. The influence of demographic and pathologic features was used in a multivariable logistic regression model to compare expected with observed HER2-positive percentages by region. RESULTS: There was significant geographic variation by California counties (11.6%-26%). The reported HER2-positive percentage was higher when the population had higher stage, tumor size, grade, percent estrogen receptor negative, younger age, or lower socioeconomic status. Ethnic distribution of the population also influenced HER2-positive percentages. Using a multivariable logistic regression model, most regions had expected values based on their population characteristics; however, "outlier" regions were identified. CONCLUSIONS: These results deepen our understanding of population characteristics' influence on the distribution of HER2-positive breast cancers. Taking these factors into account can be useful when setting laboratory benchmarks and assessing test quality.