Gain of Chromosome 6p Correlates with Severe Anaplasia, Cellular Hyperchromasia, and Extraocular Spread of Retinoblastoma
Gustav Stålhammar, Aaron M. Yeung, Pia R. Mendoza, Sander R. Dubovy, J. William Harbour, Hans E. Grossniklaus
Abstract
Purpose: Gain of chromosome 6p has been associated with poor ocular survival in retinoblastoma and histopathologic grading of anaplasia with increased risk of metastatic spread and death. This study examined the correlation between these factors and other chromosomal abnormalities as well as results of whole genome sequencing, digital morphometry, and progression-free survival. Design: Retrospective cohort study from 2 United States tertiary referral centers. Participants: Forty-two children who had undergone enucleation for retinoblastoma from January 2000 through December 2017. Methods: Status of chromosomes 6p, 1q, 9q, and 16q was evaluated with fluorescence in situ hybridization, the degree of anaplasia and presence of histologic high-risk features were assessed by ocular pathologists, digital morphometry was performed on scanned tumor slides, and whole genome sequencing was performed on a subset of tumors. Progression-free survival was defined as absence of distant or local metastases or tumor growth beyond the cut end of the optic nerve. Main Outcome Measures: Correlation between each of chromosomal abnormalities, anaplasia, morphometry and sequencing results, and survival. Results: = 0.03, Wilcoxon test). Conclusions: Gain of chromosome 6p emerges as a strong prognostic biomarker in retinoblastoma because it correlates with severe anaplasia, quantifiable changes in tumor cell staining characteristics, and extraocular spread.