Nikole O’neal

Distinct subgroups of rare brain tumors can be molecularly classified using whole genome DNA methylation profiling and next-generation sequencing. Furthermore, these tools can identify germline mutations contributing to carcinogenesis. Access to molecular testing in the clinical setting is vital for pathology laboratories to make an accurate diagnosis. One molecularly unique brain tumor requiring such tools is the papillary tumor of the pineal region (PTPR). Herein, we present a case report of a 21-year-old male presenting with macrocephaly and obstructive hydrocephalus due to the PTPR. Next-generation sequencing identified a pathogenic PTEN p.G132D mutation in the tumor and matched germline findings further identified PTEN Hamartoma Tumor Syndrome (PHTS). The case report tumor was initially misdiagnosed as ependymoma while methylation profiling classified it more specifically as a PTPR, Group B. To better understand the current status of PTPRs, we conducted a systematic review of recent cases reporting on the diagnostics, treatments, and outcomes for PTPR patients. To our knowledge, this is the first case report for PTPRs revealing an association with PHTS. Our review revealed inconsistencies in diagnostics, treatments, and outcomes for PTPR, and an underutilization of definitive molecular testing.

Personalized cancer care requires molecular characterization of neoplasms. While the research community accepts frozen tissues as the gold standard analyte for molecular assays, the source of tissue for testing in clinical cancer care comes almost universally from formalin-fixed, paraffin-embedded tissue (FFPE). As newer technologies emerge for DNA characterization that requires higher molecular weight DNA, it was necessary to compare the quality of DNA in terms of DNA length between FFPE and cryopreserved samples. We hypothesized that cryopreserved samples would yield higher quantity and superior quality DNA compared to FFPE samples. We analyzed DNA metrics by performing a head-to-head comparison between FFPE and cryopreserved samples from 38 human tumors representing various cancer types. DNA quantity and purity were measured by UV spectrophotometry, and DNA from cryopreserved tissue demonstrated a 4.2-fold increase in DNA yield per mg of tissue (p-value < 0.001). DNA quality was measured on a fragment microelectrophoresis analyzer, and again, DNA from cryopreserved tissue demonstrated a 223% increase in the DNA quality number and a 9-fold increase in DNA fragments > 40,000 bp (p-value < 0.0001). DNA from the cryopreserved tissues was superior to the DNA from FFPE samples in terms of DNA yield and quality.