Evaluation of programmed death ligand 1 expression in cytology to determine eligibility for immune checkpoint inhibitor therapy in patients with head and neck squamous cell carcinoma

CMTM6 status predicts survival in head and neck squamous cell carcinoma and correlates with PD-L1 expression

We retrospectively analyzed 129 treatment-naïve head and neck squamous cell carcinomas (HNSCCs) for the expression of programmed death ligand 1 (PD-L1), CKLF-like MARVEL transmembrane domain-containing 6 (CMTM6), tumor-infiltrating leukocytes (TILs), and tumor-associated macrophages (TAMs). We evaluated the relationships among these markers, human papilloma virus (HPV) status, and overall survival (OS). PD-L1 and CMTM6 (combined positive score (CPS) ≥ 1 and ≥ 5) were detected in ~ 70% of HNSCCs. HPV status had insignificant effects on marker expression. Most PD-L1-positive cases showed concomitant CMTM6 expression with comparable staining patterns. While PD-L1 and CMTM6 mRNA expression levels correlated with PD-L1 and CMTM6 protein status, no significant correlation was observed for PD-L1 and CMTM6 mRNA expression. Tumors expressing PD-L1 (p < 0.0001) and/or CMTM6 (p < 0.05) were associated with the best OS. A high density of TILs (p < 0.01), CD8+ T cells (p < 0.001), and CD68/CD163 ratio > 1 were prognostically relevant. In addition to HPV status, PD-L1 and CD8+ T cells, CMTM6 was identified as an independent prognostic factor using a multivariate Cox regression analysis. PD-L1 and CMTM6 correlated with TILs and CD8+ cells but not with HPV. Our results identified CMTM6 as an important interaction partner in the crosstalk between TILs, CD8+ T cells, and PD-L1, which mediates anticancer efficacy. Assessments of CMTM6 may be helpful for prognostic prediction, and it may serve as a reliable biomarker for immunotherapy selection.

Minimally invasive biopsy-based diagnostics in support of precision cancer medicine

Precision cancer medicine (PCM) to support the treatment of solid tumors requires minimally invasive diagnostics. Here, we describe the development of fine-needle aspiration biopsy-based (FNA) molecular cytology which will be increasingly important in diagnostics and adaptive treatment. We provide support for FNA-based molecular cytology having a significant potential to replace core needle biopsy (CNB) as a patient-friendly potent technique for tumor sampling for various tumor types. This is not only because CNB is a more traumatic procedure and may be associated with more complications compared to FNA-based sampling, but also due to the recently developed molecular methods used with FNA. Recent studies show that image-guided FNA in combination with ultrasensitive molecular methods also offers opportunities for characterization of the tumor microenvironment which can aid therapeutic decisions. Here we provide arguments for an increased implementation of molecular FNA-based sampling as a patient-friendly diagnostic method, which may, due to its repeatability, facilitate regular sampling that is needed during different treatment lines, to provide tumor information, supporting treatment decisions, shortening lead times in healthcare, and benefit healthcare economics.

Molecular Markers in the World Health Organization Classification of Head and Neck Tumors, Fifth Edition

The past decade has seen exponential advancements in molecular markers and the genetics of tumors, recognizing the limitations of conventional histopathology for grading, classification, and prognostication. Such advances have resulted in changes to classification systems, for example, with the incorporation of objective molecular and genetic information into the 2021 World Health Organization (WHO) classification of central nervous system tumors. The fifth edition of the WHO classification of head and neck tumors (HN5) (beta online version, 2022) also introduced major changes based on molecular markers, including additions, deletions, and reclassifications of entities, with the idea of being more objective and standardized. These changes are highly relevant to therapy decisions, prognosis, and clinical research and for patients with resistant diseases to explore options in clinical trials. The HN5, for the first time, included a radiologist as a member of the writing team to incorporate pertinent imaging findings into the classification. It is important for the radiologist, as an integral part of the multidisciplinary team, to be up to date about these changes for a better understanding of tumor biology, to integrate this into their clinical practice, and to provide more value in their interpretations. The authors provide a basic understanding of pathology and genetics for the radiologist, highlighting the molecular changes in epithelial (including squamous cell) and nonepithelial tumors of the head and neck. The authors also highlight newly recognized and reclassified tumor entities and provide a brief discussion on the genetic tumor syndromes. ©RSNA, 2024 Supplemental material is available for this article. See the invited commentary by Junn and Baugnon in this issue.

PD-L1 expression in recurrent or metastatic head and neck squamous cell carcinoma in China (EXCEED study): a multicentre retrospective study

AIMS

Programmed death-ligand 1 (PD-L1) is known to be highly expressed in various malignancies, including head and neck squamous cell carcinoma (HNSCC). We aimed to determine the prevalence of PD-L1 expression in recurrent or metastatic HNSCC (R/M HNSCC) among Chinese patients.

METHODS

This multicentre, retrospective analysis of data from six centres in China included patients with R/M HNSCC treated from 9 August 2021 to 28 February 2022. PD-L1 expression in tumour tissue was assessed and represented using a combined positive score (CPS). The χ2 and Cochran-Mantel-Haenszel χ2 tests were used to compare the prevalence of different PD-L1 expression statuses according to related co-variables.

RESULTS

For all 402 examined patients with R/M HNSCC, 168 cases (41.8%) had PD-L1 expression with a CPS ≥20, and 337 cases (83.8%) had PD-L1 expression with a CPS ≥1. Between the PD-L1 CPS ≥20 group and PD-L1 CPS <20 group, statistically significant differences were observed for variables of sex (p<0.001), smoking habit (p=0.0138 for non-smokers vs current smokers) and primary tumour site (p<0.001 for hypopharynx vs oral cavity and p=0.0304 for larynx vs oral cavity, respectively).

CONCLUSION

PD-L1 with CPS ≥20 was expressed in about 41.8% of cases with R/M HNSCC among Chinese patients, and PD-L1 expression was significantly associated with sex, smoking history and primary tumour site. Our findings regarding the variables related to PD-L1 expression level provide insight for clinical practice and a solid basis for future research on immunotherapy in HNSCC.

TRIAL REGISTRATION NUMBER

ISRCTN10570964.

Head and Neck Fine Needle Aspiration: Current and Future Impact on Patient Care

The discovery of multiple novel biomarkers in head and neck tumors has led to an increasing interest in utilizing head and neck cytology material as the primary specimens for testing diagnostic and prognostic biomarkers. Although human papillomavirus and programmed death ligand 1 are the most well-established biomarkers tested in cytology specimens, their utilization in cytology is limited by the absence of standardized protocols for specimen collection and fixation. This has led to a quest for innovative techniques to explore the genomic landscape in head and neck tumors and its application in cytology.

PD-L1 expression in fine-needle aspiration cell blocks of head and neck squamous-cell carcinoma and its cytohistological concordance

BACKGROUND

PD-L1 immunoexpression in head and neck squamous-cell carcinoma (HNSCC) determines immunotherapy eligibility. Patients are often diagnosed using fine-needle aspiration (FNA) of metastatic lymph nodes, however, the cytohistologic correlation of the combined positive score (CPS) is largely unknown.

METHODS

This study retrospectively identified 96 paired histologic (HS) and cytologic specimens (CyS), between 2016 and 2020, diagnosed with HNSCC. Cases with <100 tumor cells (n = 54) or missing block(s) (n = 8) were excluded. All 34 case pairs were scored with CPS using the PD-L1 22C3 pharmDx assay at clinically relevant cut-offs of <1%, 1%-19%, and ≥20% independently by three observers blinded to the case pairs (CyS with corresponding HS).

RESULTS

The CPS (<1/1-19/≥20) for CyS and HS were as follows: 10(29.4%)/10(29.4%)/14(41.2%) and 2(5.9%)/13(38.2%)/19(55.9%), respectively. There was fair overall cytohistologic agreement (OA) of 76.5% (k = 0.261) at the CPS cut-off of 1. The OA did not differ significantly between site-matched (n = 13) and -unmatched (n = 21) case pairs (p = .4653). CyS has a specificity and positive predictive value (PPV) of 100% but a negative predictive value (NPV) of only 20% as compared to its paired HS.

CONCLUSIONS

Our study demonstrates fair CPS cytohistologic correlation in HNSCC specimens using the PD-L1 IHC 22C3 pharmDx assay with high PPV but low NPV. This suggest that determining PD-L1 status in FNA specimens can play an important role in the clinical management of HNSCC patients.

Assessing PD-L1 Expression in Head and Neck Squamous Cell Carcinoma: Trials and Tribulations

Immune checkpoint inhibitors have improved the outcome of patients diagnosed with inoperable recurrent or metastatic head and neck squamous cell carcinoma. However, as only a subset of head and neck cancer patients benefit from this treatment, biomarkers predicting treatment response help guide physicians in their clinical decision-making. PD-L1 expression assessed by immunohistochemistry is the single most clinically relevant biomarker predicting response to PD-1-blocking antibodies. Here, we discuss in which clinical context assessment of PD-L1 expression is instrumental for the choice of therapy, how pathologists score it, and how it affects the approval of anti-PD-1 antibodies. Furthermore, we discuss the heterogeneity of PD-L1 expression and review technical aspects of determining this prominent biomarker-knowledge that might influence clinical decision-making.

Identifying Predictive Biomarkers for Head and Neck Squamous Cell Carcinoma Response

The 5-year survival rate for head and neck squamous cell carcinoma (HNSCC) is approximately 65%. In addition to radio-chemotherapy, immunotherapy is an approach in the treatment of advanced HNSCC. A better understanding of the immune context would allow personalized treatment by identifying patients who are best suited for different treatment options. In our discovery cohort, we evaluated the expression profiles of CMTM6, PD-L1, CTLA-4, and FOXP3 in 177 HNSCCs from Caucasian patients of all tumor stages and different treatment regimens, correlating marker expression in tumor and immune cells with outcomes. Patients with CMTM6high-expressing tumors had a longer overall survival regardless of treatment. This prognostic benefit of CMTM6 in HNSCC was validated in an independent cohort. Focusing on the in the discovery cohort (n = 177), a good predictive effect of CMTM6high expression was seen in patients receiving radiotherapy (p = 0.07; log rank), but not in others. CMTM6 correlated with PD-L1, CTLA-4 and FOXP3 positivity, with patients possessing CMTM6high/FOXP3high tumors showing the longest survival regardless of treatment. In chemotherapy-treated patients, PD-L1 positivity was associated with longer progression-free survival (p < 0.05). In the 27 patients who received immunotherapy, gene expression analysis revealed lower levels of CTLA-4 and FOXP3 with either partial or complete response to this treatment, while no effect was observed for CMTM6 or PD-L1. The combination of these immunomodulatory markers seems to be an interesting prognostic and predictive signature for HNSCC patients with the ability to optimize individualized treatments.

Multiple predictive biomarker testing in melanoma: Another challenge in identifying the optimal approach on cytological samples

BACKGROUND

The management of cutaneous melanoma has changed dramatically in recent years thanks to the development of tyrosine kinase and immune-checkpoint inhibitors (ICIs). Thus, multiple biomarker testing is becoming ever more important for the identification of patients who are potentially eligible for these treatments. One reliable approach to the molecular evaluation of metastatic melanoma is fine needle cytology (FNC). To examine the utility of this approach for assessing PD-L1 expression levels, we evaluated the cellular adequacy of residual cell block (CB) material from metastatic melanomas that were previously tested for BRAF and NRAS mutations.

METHODS

We retrieved from our internal archives a series of FNC samples of metastatic melanoma that had been subjected to molecular testing on residual CB material or a dedicated needle rinse between January 2016 and July 2022. Real-time polymerase chain reaction was used to assess BRAF and NRAS status, and an SP263 assay was employed to ascertain PD-L1 expression levels.

RESULTS

Overall, n = 19 cases were selected. Of these, 11 (57.9%) cases revealed a BRAF exon 15 p.V600E mutation, one case (5.3%) revealed NRAS mutation, and seven cases (36.8%) showed no mutations. Regarding PD-L1 assessment, 16/19 (84.2%) cases were deemed adequate, meaning they contained at least 100 viable cells.

CONCLUSIONS

We highlighted the feasibility of assessing PD-L1 expression levels in residual CB material from metastatic melanomas previously tested for BRAF and NRAS mutations. Moreover, we pointed out that FNC needle rinses may be an alternative source of nucleic acids for molecular testing, preserving CB material for immunocytochemistry evaluation.

PD-L1 immunohistochemical testing: A review with reference to cytology specimens

BACKGROUND

Immunotherapy based on disruption of the PD-1/PD-L1 axis is standard of care for many high stage malignancies including melanomas, non-small cell carcinomas of the lung, triple negative breast carcinomas, and squamous cell carcinomas of the head and neck. Eligibility for immunotherapy requires immunohistochemical assessment of PD-L1 expression. Currently, many high stage malignancies are diagnosed by cytology and cytologic material is the only specimen available for ancillary testing. Formal guidelines do not currently exist defining the optimal specimen type, antibody to be used or the best scoring system for cytologic material. Significant information has been published for PD-L1 testing of pulmonary specimens but much less data exists for the reproducibility, accuracy and best practices for material obtained from other body sites and types of malignancy.

METHODS

We searched the PubMed data base for manuscripts relating to PD-L1 testing of cytologic specimens. The search period was between 2016 and 2022. The search terms used were PD-L1, cytology, FNA, immunotherapy, immunohistochemistry, immunocytochemistry, cytology-histology correlation. Cross referencing techniques were used to screen for the most relevant manuscripts. The abstracts of these were then reviewed for final data collection and analysis.

RESULTS

A total of 86 studies were identified conforming to study relevancy. These were reviewed in their entirety by two authors (LJL, TZ) for extraction of data. The majority of studies involved pulmonary specimens (79) with three relating to PD-L1 testing of head and neck cytologic specimens and one each for PD-L1 testing of cytology specimens from melanomas, pancreas, pleural fluids, and triple negative breast carcinomas. While smears could be used, most studies found cell blocks optimal for testing.

SUMMARY

Currently, four drugs are approved for immunotherapy based on PD-L1 status. These drugs require specific antibody clones as well as scoring systems. Scoring systems and cut points vary with the type of neoplasm being treated. Cytology specimens from the lung, head and neck and melanomas can all be used for PD-L1 testing with good agreement with corresponding histology specimens.

Atlas of PD-L1 for Pathologists: Indications, Scores, Diagnostic Platforms and Reporting Systems

Background. Innovative drugs targeting the PD1/PD-L1 axis have opened promising scenarios in modern cancer therapy. Plenty of assays and scoring systems have been developed for the evaluation of PD-L1 immunohistochemical expression, so far considered the most reliable therapeutic predictive marker. Methods. By gathering the opinion of acknowledged experts in dedicated fields of pathology, we sought to update the currently available evidence on PD-L1 assessment in various types of tumors. Results. Robust data were progressively collected for several anatomic districts and leading international agencies to approve specific protocols: among these, TPS with 22C3, SP142 and SP263 clones in lung cancer; IC with SP142 antibody in breast, lung and urothelial tumors; and CPS with 22C3/SP263 assays in head and neck and urothelial carcinomas. On the other hand, for other malignancies, such as gastroenteric neoplasms, immunotherapy has been only recently introduced, often for particular histotypes, so specific guidelines are still lacking. Conclusions. PD-L1 immunohistochemical scoring is currently the basis for allowing many cancer patients to receive properly targeted therapies. While protocols supported by proven data are already available for many tumors, dedicated studies and clinical trials focusing on harmonization of the topic in other still only partially explored fields are surely yet advisable.

PD-L1 expression in head and neck carcinoma by combined positive score: a comparison among preoperative biopsy, tumor resection, and lymph node metastasis

Immune checkpoint inhibitors have recently been approved for the treatment of advanced head and neck squamous cell carcinoma (HNSCC). The determination of PD-L1 using the combined positive score (CPS) is of utmost importance in the selection of patients. However, it is unclear which material should be examined. This study aimed to compare PD-L1 CPS in the resections of primary tumors and metastatic lymph nodes, and in the biopsies of the primary tumors.We collected 30 resected HNSCCs with lymph node metastases; in 17 of these, preoperative biopsies were retrieved. PD-L1 immunostaining of 75 samples was performed using the Dako 22C3 antibody on the Ventana ULTRA platform. An appropriate internal control was performed on each slide. CPS was calculated for each reaction. Concordance values and k were calculated for each patient. CPS cut-off values were fixed at 0 and 20.Tumors were resected from the oral cavity (4), oropharynx (17), hypopharynx (1), and larynx (8). The overall concordance of CPS between tumor resection and lymph node metastasis was 76.7% (k = 0.593). The overall concordance of CPS between tumor resection and tumor biopsy was 86.7% (k = 0.688). The agreement was moderate to substantial for each comparison.PD-L1 CPS may be correctly determined not only in resected primary tumors, but also in removed lymph node metastases, as well as in preoperative biopsies.

Roles of Major RNA Adenosine Modifications in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer malignancy worldwide and is known to have poor prognosis. The pathogenesis behind the development of HNSCC is not fully understood. Modifications on RNA are involved in many pathophysiological processes, such as tumor development and inflammation. Adenosine-related RNA modifications have shown to be linked to cancer and may play a role in cancer occurrence and development. To date, there are at least 170 different chemical RNA modifications that modify coding and non-coding RNAs (ncRNAs). These modifications affect RNA stability and transcription efficiency. In this review, we focus on the current understanding of the four major RNA adenosine modifications (N⁶-Methyladenosine, N¹-Methyladenosine, Alternative Polyadenylation Modification and A-to-I RNA editing) and their potential molecular mechanisms related to HNSCC development and progression. We also touch on how these RNA modifications affect treatment of HNSCCs.

PD-L1 evaluation in head and neck squamous cell carcinoma: Insights regarding specimens, heterogeneity and therapy

Immunohistochemical assessment with combined positive score (CPS) of programmed death-ligand 1 (PD-L1) is the prerequisite for administration of checkpoint inhibitor therapy in head and neck squamous cell carcinoma (HNSCC). Practicing pathologists are required to assess PD-L1 in routinary work and can be faced up with practical issues not always addressed in clinical trials or guidelines, such as choice of specimen to test, the intrinsic heterogeneity in PD-L1 expression in tumors and the potential impact of already administered therapy, given that patients' material can be procured at several times of cancer natural history. In the present work, we review and discuss the recent literature regarding the assessment of PD-L1 in HNSCC from the perspective of the practicing pathologist, providing some evidence on the single issues. It emerges a general trend to an underestimation of PD-L1 expression in biopsies compared to resection specimens and to a higher degree of positivity in metastatic lymph nodes in respect to primary tumors. Moreover, therapy shows to have contrasting effect on PD-L1 expression. Although further studies are needed, taking into account the intrinsic heterogeneity in PD-L1 expression and the conflicting evidences, it may be speculated that the most recent material of patients in respect to the natural history of tumor can be the most reliable to evaluate PD-L1 expression.