Pleomorphic giant cell carcinoma of prostate: Rare tumor with unique clinicopathological, immunohistochemical, and molecular features.

Pleomorphic giant cell carcinoma (PGCC) of the prostate is a rare entity categorized as a variant of prostatic acinar adenocarcinoma in the 2016 World Health Organization (WHO) classification system. PGCC differs from conventional prostatic adenocarcinoma by having bizarre, markedly enlarged, and pleomorphic cells. It differs from high grade urothelial carcinoma by negativity for urothelial differentiation markers, and can be distinguished from sarcomatoid carcinoma by lack of spindle cells. Including two new cases described herein, there have been 51 cases of prostate PGCC reported in the English literature. Clinical features shared by cases of prostate PGCC include poor prognosis, occurrence in older patients, and frequent association with prior therapy. Pathologic features common to cases of prostate PGCC include admixture with a high-grade conventional prostate carcinoma component and absent or reduced expression of prostate differentiation markers. More recent studies have begun to elucidate the molecular characteristics of PGCC, detecting specific mutations and chromosomal translocations, and showing evidence of a high degree of molecular instability in these tumors. We report novel findings in two cases of PGCC including a PIK3CA p.His1047Arg mutation not previously described. One of our cases is the first to clearly demonstrate chronological loss of prostate markers during dedifferentiation from prior conventional prostate carcinoma to PGCC. Herein, we present our two new cases and comprehensively review the literature on all reported cases of PGCC with critical commentary on findings in cases of this rare tumor.

A retrospective analysis of molecular testing in cytologically indeterminate thyroid nodules with histologic correlation: Experience at a heterogenous multihospital system.

INTRODUCTION: Thyroid malignancy is one of the most common types of cancer in developed nations. Currently, fine-needle aspiration cytology (FNAC) is the most practical screening test for thyroid nodules. However, cytologically indeterminate samples comprise approximately 15%-30% of cases. These include cases classified as atypia of undetermined significance (AUS), follicular neoplasm (FN), and suspicious for malignancy (SFM). Indeterminate cases can be sent for molecular testing for more definitive classification to help guide management and prevent overtreatment of benign thyroid nodules. We conducted a retrospective review on molecular testing of indeterminate thyroid FNAC and reviewed subsequent histologic diagnoses in resection specimens to assess how molecular testing supported a diagnosis and its effect on clinical management of patients at our institution. METHODS: A retrospective chart review was performed on all thyroid FNAC specimens, corresponding molecular testing, and subsequent surgical resection specimens over a 6-year period. RESULTS: A total of 10,253 thyroid FNAC were performed in our hospital system during our study period, of which 10% (n = 1102/10,253) had indeterminate FNAC results. Molecular testing was performed in 16% (n = 178/1102) of indeterminate cytology cases. Genetic alterations were identified in 39% (n = 69/178) of the cases sent for molecular testing. The majority of cytologically indeterminate cases sent for molecular testing were follicular-patterned lesions and their corresponding resection specimens revealed mostly low grade follicular derived neoplasms (i.e., follicular adenoma, non-invasive follicular thyroid neoplasm with papillary-like nuclear features, and follicular variant of papillary thyroid carcinoma). Of the cases with identified genetic alterations, 75% (n = 52/69) were treated surgically. In cases with no genetic alterations identified, only 18% (n = 20/109) were treated surgically. DISCUSSION/CONCLUSION: Molecular testing on cytologically indeterminate thyroid nodules can help provide a more accurate risk of malignancy assessment in patients with lesions that are difficult to diagnosis based solely on FNAC morphology. The types of genetic alterations identified in the resected thyroid lesions were consistent with what has been previously described in the literature. Additionally, we found that in the patients with indeterminate thyroid FNAC with adjunct molecular testing, more than half did not undergo surgical resection. This finding emphasizes the value of adding molecular testing in patients, particularly when attempting to reduce unnecessary surgical intervention.

Molecular Signatures of KRAS-Mutated Lung Adenocarcinoma: Analysis of Concomitant EGFR, ALK, STK11, and PD-L1 Status.

Background: KRAS mutations are the most common oncogenic driver mutations of non-small cell lung cancer (NSCLC) in the Western world. Mutations of the KRAS gene are most prevalent in the patient population of current and former cigarette smokers. With the recent pivotal approval of a targeted inhibitor therapy for patients with KRAS p.G12C mutated and pretreated NSCLC, analysis of the heterogeneity of KRAS mutations and concomitant molecular alterations in patients with these tumors at all clinical stages is indicated. Methods: In this retrospective analysis, patient pathology records were reviewed for all cases receiving a pathologic diagnosis of NSCLC within our hospital system. All data were collected with IRB approval. Cases of indeterminate tumor type favoring a non-lung primary, as well as non-adenocarcinoma NSCLC (eg, squamous) were excluded from the cohort. In this hospital system, molecular testing for KRAS mutations is part of a molecular biomarker panel that is reflex ordered at initial diagnosis by the pathologist and may be performed as a single gene test or as a solid organ cancer hotspot panel by next generation sequencing. For each patient, KRAS mutational status and specific KRAS mutations, if present, were collated. Additional information assessed for this study included patient demographics (age, gender, and smoking history), tumor staging if available, PD-L1 expression levels by immunohistochemistry (IHC), and the presence of other genetic alterations (EGFR, ALK, and STK11). Results: Between January 1, 2017 and January 1, 2019, there were 276 patients diagnosed with NSCLC of all stages who had KRAS mutational analysis performed in our hospital system and who met the criteria for inclusion into the study cohort. A KRAS driver mutation was detected in 29% of these patients. The most frequently identified KRAS mutation was p.G12C (38%), followed by p.G12D (21%) and p.G12V (13%). KRAS-mutated lung adenocarcinoma was significantly associated with current or former patient smoking status in this cohort (29/202 (14%) smokers and 1/74 (1%) non-smokers; P = .0006). PD-L1 expression of at least 1% by IHC was present in 43% of KRAS-mutated lung adenocarcinomas and 45% of non-KRAS-mutated adenocarcinomas. In this study, KRAS mutations were not found to co-occur with gene alterations in EGFR, ALK, or STK11. In 48% of cases, at least one genetic alteration (KRAS, ALK, EGFR, or STK11) was identified. Conclusions: In this study cohort, KRAS-mutated lung adenocarcinoma demonstrated significant mutational heterogeneity, which is consistent with previously published studies. KRAS mutational status was also significantly associated with a current or former smoking history. Notably, p.G12C was the most frequently identified KRAS mutation in this cohort, with a frequency of 38%. This finding is particularly relevant given the recent approval of a KRAS p.G12C-specific targeted inhibitor therapy and the continued development of additional KRAS targeted therapies that may prove effective in treating NSCLC. These findings also highlight the necessity of considering molecular testing for KRAS mutations in patients with NSCLC and a smoking history, as this population most frequently harbors KRAS mutations and may benefit from these emerging targeted therapies.

Outcomes and prognostic contributors in patients with KRAS mutated non-small cell pulmonary adenocarcinomas: a single institution experience.

BACKGROUND: KRAS is the most frequently encountered driver mutation in advanced non-small cell lung cancer (NSCLC). With targeted therapy for the most common KRAS mutation p.G12C on the horizon, the aim of this study is to retrospectively report outcomes in patients with KRAS mutated NSCLC. METHODS: This was a retrospective chart review of 7 hospitals in Texas with reflex biomarker testing in all lung adenocarcinomas. Patients were included if they had pathologically diagnosed adenocarcinoma of any stage originating in the lung with molecularly confirmed KRAS driver mutation of any genotypic subtype. Twelve-month survival was assessed and compared between KRAS p.G12C and all other detected KRAS mutations. Other outcomes including impact of age, sex, smoking status, and pack years smoked were assessed to determine if they had prognostic significance on mortality in KRAS mutated patients. RESULTS: There were 58 patients diagnosed with KRAS mutated NSCLC, 63.8% were at an advanced stage at diagnosis, 55.8% of patients were female, and 82.8% were white. The median age was 72 [52-88] years, and 93.1% were either current or prior smokers. KRAS p.G12C was the most common KRAS mutation (44.8%). At diagnosis, patients with KRAS p.G12C had poorer performance statuses compared to other KRAS mutations. A total of 32 (55.2%) patients died, 26 with advanced disease. In this study, current smoking status (P=0.1652), pack years smoked (P=0.6597), age (P=0.5092), sex (P=0.4309), and underlying KRAS codon mutation controlling for stage (P=0.2287) did not impact survival. However, KRAS p.G12C had a numerically lower 12 months overall survival (OS) compared to all other KRAS mutations in both early stage (56.3% vs. 90.9%) and advanced stage (25.0% vs. 47.6%) disease. Of note, 16 (27.6%) patients had prior, concurrent, or second malignancies, but these did not significantly impact OS (P=0.7696). CONCLUSIONS: This study did not find a prognostic difference with sex, smoking history, age, or p.G12C mutation. The patients in this cohort with KRAS p.G12C had a numerically lower 12-month overall survival in both early and advanced stage disease compared to other mutations, and over one-quarter had a notable history of previous and second primary malignancies.

A BRAF V600E Mutation in RET-Negative Medullary Thyroid Cancer.

We report the case of a woman with a sporadic medullary thyroid carcinoma. Genomic analysis found that her tumor did not contain any common RET mutations but did harbor a BRAF V600E mutation. Only one other well-confirmed example of the BRAF V600E mutation has been reported in an MTC patient. We conclude that this common BRAF mutation may independently drive neoplastic transformation of human parafollicular C cells.

Development and validation of Houston Methodist Variant Viewer version 3: updates to our application for interpretation of next-generation sequencing data.

OBJECTIVES: Informatics tools that support next-generation sequencing workflows are essential to deliver timely interpretation of somatic variants in cancer. Here, we describe significant updates to our laboratory developed bioinformatics pipelines and data management application termed Houston Methodist Variant Viewer (HMVV). MATERIALS AND METHODS: We collected feature requests and workflow improvement suggestions from the end-users of HMVV version 1. Over 1.5 years, we iteratively implemented these features in five sequential updates to HMVV version 3. RESULTS: We improved the performance and data throughput of the application while reducing the opportunity for manual data entry errors. We enabled end-user workflows for pipeline monitoring, variant interpretation and annotation, and integration with our laboratory information system. System maintenance was improved through enhanced defect reporting, heightened data security, and improved modularity in the code and system environments. DISCUSSION AND CONCLUSION: Validation of each HMVV update was performed according to expert guidelines. We enabled an 8× reduction in the bioinformatics pipeline computation time for our longest running assay. Our molecular pathologists can interpret the assay results at least 2 days sooner than was previously possible. The application and pipeline code are publicly available at https://github.com/hmvv.

Clinical Utility of Reflex Ordered Testing for Molecular Biomarkers in Lung Adenocarcinoma.

INTRODUCTION: In order to standardize and expedite molecular biomarker testing, we implemented reflex ordered testing of targeted gene alterations in newly diagnosed lung adenocarcinomas within our hospital system. PATIENTS AND METHODS: Reflex ordered testing of specific molecular biomarkers at the time of pathologic diagnosis of lung adenocarcinoma was approved and adopted system-wide in our hospital during 2017. Through institutional review board approval, we retrospectively looked at cohort of patients whose specimens received a diagnosis of lung adenocarcinoma, with molecular biomarker testing performed at Houston Methodist Hospital between 2016 and 2018. We compared average turnaround time (TAT) from 2016 (prior to reflex ordered testing) to 2017 and 2018 (post reflex ordered testing). RESULTS: Standard molecular testing performed on 39 patients in 2016 had an average TAT of 52.6 days, whereas reflex ordered molecular testing in 2017 yielded an average TAT of 26.5 days (n = 127) and 15.6 days in 2018 (n = 54). The average TAT for reporting of molecular results significantly decreased by 37 days (P = .0002) within our hospital system post adoption of reflex ordered testing for lung adenocarcinoma. Reflex ordered testing also resulted in a higher variant detection rate than standard molecular biomarker ordering practices (48.8% vs. 25.6%; P < .05). Overall, the frequencies and types of variants identified among our cohort were similar to previous reports. CONCLUSIONS: Reflex ordered testing of molecular biomarkers in lung adenocarcinoma led to significantly decreased TAT within our hospital system and higher detection rates of targeted gene alterations.

Pathology Trainee Redeployment and Education During the COVID-19 Pandemic: An Institutional Experience.

Pathology training programs throughout the United States have endured unprecedented challenges dealing with the ongoing coronavirus disease 2019 pandemic. At Houston Methodist Hospital, the Department of Pathology and Genomic Medicine planned and executed a trainee-oriented, stepwise emergency response. The focus was on optimizing workflows among areas of both clinical and anatomic pathology, maintaining an excellent educational experience, and minimizing trainee exposure to coronavirus disease 2019. During the first phase of the response, trainees were divided into 2 groups: one working on-site and the other working remotely. With the progression of the pandemic, all trainees were called back on-site and further redeployed within our department to meet the significantly increased workload demands of our clinical laboratory services. Adjustments to trainee educational activities included, among others, the organization of a daily coronavirus disease 2019 virtual seminar series. This series served to facilitate communication between faculty, laboratory managers, and trainees. Moreover, it became a forum for trainees to provide updates on individual service workflows and volumes, ongoing projects and research, as well as literature reviews on coronavirus disease 2019-related topics. From our program's experience, redeploying pathology trainees within our department during the coronavirus disease 2019 pandemic resulted in optimization of patient care while ensuring trainee safety, and importantly, helped to maintain continuous high-quality education through active involvement in unique learning opportunities.

Houston Methodist Variant Viewer: An Application to Support Clinical Laboratory Interpretation of Next-generation Sequencing Data for Cancer.

INTRODUCTION: Next-generation-sequencing (NGS) is increasingly used in clinical and research protocols for patients with cancer. NGS assays are routinely used in clinical laboratories to detect mutations bearing on cancer diagnosis, prognosis and personalized therapy. A typical assay may interrogate 50 or more gene targets that encompass many thousands of possible gene variants. Analysis of NGS data in cancer is a labor-intensive process that can become overwhelming to the molecular pathologist or research scientist. Although commercial tools for NGS data analysis and interpretation are available, they are often costly, lack key functionality or cannot be customized by the end user. METHODS: To facilitate NGS data analysis in our clinical molecular diagnostics laboratory, we created a custom bioinformatics tool termed Houston Methodist Variant Viewer (HMVV). HMVV is a Java-based solution that integrates sequencing instrument output, bioinformatics analysis, storage resources and end user interface. RESULTS: Compared to the predicate method used in our clinical laboratory, HMVV markedly simplifies the bioinformatics workflow for the molecular technologist and facilitates the variant review by the molecular pathologist. Importantly, HMVV reduces time spent researching the biological significance of the variants detected, standardizes the online resources used to perform the variant investigation and assists generation of the annotated report for the electronic medical record. HMVV also maintains a searchable variant database, including the variant annotations generated by the pathologist, which is useful for downstream quality improvement and research projects. CONCLUSIONS: HMVV is a clinical grade, low-cost, feature-rich, highly customizable platform that we have made available for continued development by the pathology informatics community.

Characterization of SIV in the oral cavity and in vitro inhibition of SIV by rhesus macaque saliva.

Human immunodeficiency virus (HIV) infections are rarely acquired via an oral route in adults. Previous studies have shown that human whole saliva inhibits HIV infection in vitro, and multiple factors present in human saliva have been shown to contribute to this antiviral activity. Despite the widespread use of simian immunodeficiency virus (SIV)-infected rhesus macaques as models for HIV pathogenesis and transmission, few studies have monitored SIV in the oral cavity of infected rhesus macaques and evaluated the viral inhibitory capacity of macaque saliva. Utilizing a cohort of rhesus macaques infected with SIV(Mac251), we monitored virus levels and genotypic diversity in the saliva throughout the course of the disease; findings were similar to previous observations in HIV-infected humans. An in vitro infectivity assay was utilized to measure inhibition of HIV/SIV infection by normal human and rhesus macaque whole saliva. Both human and macaque saliva were capable of inhibiting HIV and SIV infection. The inhibitory capacity of saliva samples collected from a cohort of animals postinfection with SIV increased over the course of disease, coincident with the development of SIV-specific antibodies in the saliva. These findings suggest that both innate and adaptive factors contribute to inhibition of SIV by whole macaque saliva. This work also demonstrates that SIV-infected rhesus macaques provide a relevant model to examine the innate and adaptive immune responses that inhibit HIV/SIV in the oral cavity.