PD-L1 (22C3) Expression Correlates with Clinical and Molecular Features of Lung Adenocarcinomas in Cytological Samples.

INTRODUCTION: PD-L1 expression is the most widely used predictive marker for immune checkpoint inhibitor (ICI) therapy in patients with lung adenocarcinoma. However, the current understanding of the association between PD-L1 expression and treatment response is suboptimal. A significant percentage of patients have only a cytological specimen available for clinical management. Therefore, it is relevant to examine the impact of molecular features on PD-L1 expression in cytological samples and how it might correlate with a therapeutic response. METHODS: We evaluated patients diagnosed with adenocarcinoma of the lung who had both in-house targeted next-generation sequencing analysis and paired PD-L1 (22C3) immunohistochemical staining performed on the same cell blocks. We explored the association between molecular features and PD-L1 expression. In patients who underwent ICIs therapy, we assessed how a specific gene mutation impacted a therapeutic response. RESULTS: 145 patients with lung adenocarcinoma were included in this study. PD-L1-high expression was found to be more common in pleural fluid than in other sample sites. Regional lymph node samples showed a higher proportion of PD-L1-high expression (29%) compared with lung samples (6%). The predictive value of PD-L1 expression was retained in cytological samples. Mutations in KRAS were also associated with a PD-L1-high expression. However, tumors with TP53 or KRAS mutations showed a lower therapy response rate regardless of the PD-L1 expression. CONCLUSION: Cytological samples maintain a predictive value for PD-L1 expression in patients with lung adenocarcinoma as regards the benefit of ICI treatment. Specific molecular alterations additionally impact PD-L1 expression and its predictive value.

High-risk human papillomavirus testing in cytology aspiration samples from the head and neck part 2: a survey of the American Society of Cytopathology community.

INTRODUCTION: High-risk human papillomavirus (HR-HPV) status is critical in the diagnosis of oropharyngeal squamous cell carcinoma, informing prognosis and choice of therapy. HR-HPV status additionally plays a key role in the evaluation of squamous cell carcinoma of unknown origin metastatic to cervical lymph nodes. Thus, HR-HPV testing of fine needle aspirate (FNA) specimens from the head and neck is invaluable for accurate diagnosis, prognostication, and treatment planning. MATERIALS AND METHODS: American Society of Cytopathology members were surveyed to understand the current state of HR-HPV testing on FNA samples from the head and neck. The survey focused on 3 main topic areas: practice setting of respondents, methods of collection and processing of aspirate specimens for HR-HPV testing, and validation of HR-HPV testing methodologies on aspirate samples. RESULTS: The survey reveals that laboratories employ various methods to detect HR-HPV in FNA samples, most commonly p16 immunohistochemical staining of cell block sections. Although some laboratories have independently validated their HR-HPV detection method, such validation is not universal. Finally, not all respondents currently have HR-HPV testing available, but approximately half of those without a testing method desire to make HR-HPV testing of FNA samples available. CONCLUSIONS: Survey responses highlight that various testing modalities are utilized for HR-HPV detection in aspirate samples. However, internal laboratory validation of HR-HPV testing for FNA specimens is not ubiquitous despite professional society recommendations.

Cross-contamination in cytology processing: a review of current practice.

INTRODUCTION: New cytopreparatory technologies decrease the need for direct smears in favor of an increased use of liquid-based cytology methods. Despite these practice changes, Clinical Laboratory Improvement Amendments continue to require that cytopathology laboratories have procedures to prevent cross-contamination (CC). While the incidence of CC is not well documented, specific cytologic preparations and specimens with a high potential for CC have not been generally defined by professional guidelines or consensus. The American Society of Cytopathology Clinical Practice Committee surveyed cytology practitioners to better understand current practice related to CC in cytology. MATERIALS AND METHODS: The survey focused on four topics: (1) practice settings and demographic data; (2) current practice for meeting CC requirements; (3) practice for rapid on-site evaluation; and (4) preparation types considered high risk for CC. The survey was sent to all American Society of Cytopathology and American Society for Cytotechnology members from July 1 to August 14, 2020. RESULTS: Ninety-eight percent of laboratories had a written CC policy, with 66.18% of the policies addressing rapid on-site evaluation CC procedures. Documented cases of CC were rare. Alcohol-fixed, direct smears of Pap-stained fluids were deemed the most likely to be impacted by CC. Cell block contamination during the histologic processing were reported by 56.20% of respondents. CONCLUSIONS: Changes in practice has resulted in decreased preparation types associated with a high potential for CC. Laboratories should follow a risk-based approach to define these cases. Knowledge of practice patterns among laboratories can guide the development and refinement of policy and procedures.