A case of molecularly confirmed BAP1 inactivated melanocytic tumor with retention of immunohistochemical expression: A confounding factor.

BRCA1-associated Protein 1 (BAP1)-inactivated melanocytic nevi/tumors (BIMT) have distinct morphologic features. A typical case exhibits a biphasic population of cytologically bland conventional melanocytes and a second proliferation of larger epithelioid melanocytes with abundant eosinophilic cytoplasm. The vast majority of cases harbor BRAF V600E in both components with bi-allelic inactivation of BAP1 in the epithelioid component by various molecular mechanisms resulting in loss of nuclear protein expression, which can be demonstrated by immunohistochemistry. We present a case of BIMT with histopathologic features highly suggestive of this entity but unexpected retention of nuclear expression of the BAP1 protein. Subsequent molecular tests showed heterozygous loss of the BAP1 locus on the short arm of chromosome 3 (3p21.1) by chromosomal microarray analysis (CMA) and a suspected c.505C>T p.H169Y pathogenic variant identified by DNA sequencing that was subsequently confirmed by primer-specific SNaPshot mini-sequencing. In light of the heterozygous deletion of BAP1, this variant in the remaining allele encodes a catalytically inactive BAP1 mutant protein as shown in functional studies. The presence of a nonfunctional allele within the nucleus combined with a heterozygous deletion of BAP1 explains the clear and characteristic BIMT morphology observed by histopathology. This case underlines the potential importance of molecular diagnostics when protein expression studies do not correlate with morphology.

Screening for Human Papillomavirus in a Low- and Middle-Income Country.

PURPOSE: Low- and middle-income countries have high incidences of cervical cancer linked to human papillomavirus (HPV), and without resources for cancer screenings these countries bear 85% of all cervical cancer cases. To address some of these needs, brigade-style screening combined with sensitive polymerase chain reaction-based HPV testing to detect common high-risk HPV genotypes may be necessary. METHODS: We deployed an inexpensive DNA extraction technique and a real-time polymerase chain reaction-based HPV genotyping assay, as well as Papanicolaou testing, in a factory in San Pedro Sula, Honduras, where 1,732 women were screened for cervical cancer. RESULTS: We found that 28% of participants were positive for high-risk HPV, with 26% of HPV-positive participants having more than one HPV infection. Moreover, the most common HPV genotypes detected were different than those routinely found in the United States. CONCLUSION: This work demonstrates a deployable protocol for HPV screening in low- and middle-income countries with limited resources to perform cytopathology assessment of Pap smears.

BAP1-deficient tumor/nevus with germline aberration: A potential pitfall in assessing melanocytic neoplasms with single nucleotide polymorphism array.

BRCA1-associated protein 1 (BAP1) is a tumor suppressor gene, located on chromosome 3p21, encoding BAP1 nuclear protein, which is associated with a subset of melanocytic tumors with distinct cytologic features. Single nucleotide polymorphism array (SNP-array) is a molecular karyotyping technique that can detect copy number variations and loss of heterozygosity in various fresh and formalin-fixed paraffin-embedded tissues. Herein we present a 56-year-old female, who presented with a lesion on her left nose/cheek that was growing in size and changing in color. Histopathology was characteristic of a BAP1-deficient melanocytic neoplasm, with a biphasic population of cytologically bland conventional nevomelanocytes and a proliferation of large epithelioid melanocytes with abundant eosinophilic cytoplasm. Immunohistochemistry for BAP1 showed loss of nuclear labeling in the epithelioid melanocytes. SNP-array revealed a chromosome 21q22.1 monoaberration with no chromosome 3 abnormalities. The detection of this aberration prompted a discussion as to whether the lesion was best designated as a nevus or tumor. SNP-array on the patient's blood showed the same monoaberration of chromosome 21q22.1. This case emphasizes the importance of interpreting microarray results in the context of morphology, as germline aberrations can be a pitfall when assessing the genomic stability of a melanocytic proliferation by SNP array.

Mucosal inflammation in Candida esophagitis has distinctive features that may be helpful diagnostically.

The diagnosis of Candida esophagitis can be challenging when the epithelium containing Candida filamentous forms is not readily seen or is entirely sloughed away. Mucosal inflammation could be helpful diagnostically, if distinctive. However it is thought to be nonspecific in Candida esophagitis. The goal of this retrospective study was to identify features of mucosal inflammation helpful in alerting a pathologist to the possibility of Candida esophagitis when Candida mycelia are not readily observed. The study group consisted of 99 consecutive cases of Candida esophagitis and a control group of 64 consecutive cases of reflux esophagitis diagnosed at our institution from 2008-2016. Band-like superficial intraepithelial neutrophils and increased intraepithelial lymphocytes were observed in 75 and 67% of Candida esophagitis cases, respectively and only in 14 and 19% of reflux esophagitis cases, respectively (p < .0001). Intraepithelial lymphocytes were peripapillary or CD4-predominant in 75% of Candida esophagitis cases with increased lymphocytes, in contrast to 17% of reflux esophagitis cases (p = .0011). Concurrent presence of intraepithelial neutrophils and increased lymphocytes showed increased specificity for Candida esophagitis and was observed in 61% of patients with Candida esophagitis and only in 2% of patients with reflux esophagitis (p < .0001). In addition, superficial band-like neutrophils were observed concurrently with increased peripapillary lymphocytes or CD4-predominant lymphocytes in 35 and 50% of Candida esophagitis cases, respectively, in contrast to no reflux esophagitis cases. Basal cell hyperplasia and elongation of stromal papillae were frequent in both groups. The data suggest that when Candida microorganisms are not readily observed, concurrent presence of superficial band-like neutrophils and increased lymphocytes may be indicative of Candida etiology of active esophagitis.

Yeast Integral Membrane Proteins Apq12, Brl1, and Brr6 Form a Complex Important for Regulation of Membrane Homeostasis and Nuclear Pore Complex Biogenesis.

Proper functioning of intracellular membranes is critical for many cellular processes. A key feature of membranes is their ability to adapt to changes in environmental conditions by adjusting their composition so as to maintain constant biophysical properties, including fluidity and flexibility. Similar changes in the biophysical properties of membranes likely occur when intracellular processes, such as vesicle formation and fusion, require dramatic changes in membrane curvature. Similar modifications must also be made when nuclear pore complexes (NPCs) are constructed within the existing nuclear membrane, as occurs during interphase in all eukaryotes. Here we report on the role of the essential nuclear envelope/endoplasmic reticulum (NE/ER) protein Brl1 in regulating the membrane composition of the NE/ER. We show that Brl1 and two other proteins characterized previously-Brr6, which is closely related to Brl1, and Apq12-function together and are required for lipid homeostasis. All three transmembrane proteins are localized to the NE and can be coprecipitated. As has been shown for mutations affecting Brr6 and Apq12, mutations in Brl1 lead to defects in lipid metabolism, increased sensitivity to drugs that inhibit enzymes involved in lipid synthesis, and strong genetic interactions with mutations affecting lipid metabolism. Mutations affecting Brl1 or Brr6 or the absence of Apq12 leads to hyperfluid membranes, because mutant cells are hypersensitive to agents that increase membrane fluidity. We suggest that the defects in nuclear pore complex biogenesis and mRNA export seen in these mutants are consequences of defects in maintaining the biophysical properties of the NE.