Low incidence of BRAF and NRAS mutations in a population with a high incidence of melanoma

Reported rates of BRAF mutation in Irish cutaneous melanoma cohorts are lower than the reported international data. We aimed to assess the mutational status of a cohort of primary cutaneous melanomas and to correlate it with clinical follow-up data.A total of 92 cases of primary cutaneous melanoma diagnosed at a single institution in 2012 were analyzed. Regions containing common mutations in the BRAF, NRAS, KIT, and KRAS genes were investigated by PCR amplification followed by Sanger sequencing. Demographic details, tumor characteristics, and 10-year outcome data were also obtained.Ten cases with BRAF V600E mutations (11.6%) and five (5.49%) NRAS mutations (4 at Q61R, 1 at Q61K) were detected. No statistically significant differences were noted between groups for age, gender, depth of invasion, nodal status, or recurrence status (p ≥ 0.05).These findings suggest that the Irish population has a markedly lower incidence of BRAF and NRAS mutations in melanoma than those reported in other cohorts.

Aberrant p16, p53 and Ki-67 immunohistochemistry staining patterns can distinguish solitary keratoacanthoma from cutaneous squamous cell carcinoma

Keratoacanthoma (KA) is widely considered a benign, usually self-resolving, neoplasm distinct from cutaneous squamous cell carcinoma (cSCC), while some consider KA to be indistinguishable from cSCC. Published studies indicate utility for p16, p53, Ki-67 immunostaining and elastic van Gieson (EVG) in the assessment of KA and cSCC. We compared clinical features and staining patterns for p16, p53, Ki-67 and EVG in fully excised KA, cSCC with KA-like features (cSCC-KAL) and other cSCC (cSCC-OTHER). Significant differences between KA, cSCC-KAL and cSCC-OTHER were found for head and neck location (20%, 86%, 84%), and duration <5 months (95%, 63%, 36%). KA shows both a mosaic pattern for p16 (>25-90% of neoplasm area) and peripheral graded pattern for p53 (up to 50% moderate and strong nuclear staining) in 92% compared with 0% of cSCC-KAL and 0% of cSCC-OTHER. In contrast, a highly aberrant pattern (usually null) for one or both p16 and p53, was present in 0% of KA, 83.8% of cSCC-KAL and 90.9% of cSCC-OTHER. Abnormal distribution of Ki-67 beyond the peripheral 1-3 cells was uncommon in KA (4.2%) and common in cSCC-KAL (67.6%) and cSCC-OTHER (88.4%). Moderate to striking entrapment of elastic and collagen fibres was present in the majority of KA (84%), cSCC-KAL (81%) and cSCC-OTHER (65%). KA are clinically distinct neoplasms typically of short duration occurring preferentially outside the head and neck and generally lacking aberrations of p16, p53 and Ki-67, compared with cSCC that have high rates of aberrant or highly aberrant p16, p53 and Ki-67, but EVG lacked specificity.

PAPA-like syndrome with heterozygous mutation in the MEFV gene

A patient presented with a history of recurrent pyoderma gangrenosum, arthritis and extensive acne, prompting a genetic workup for PAPA syndrome. An MEFV mutation was identified and a change in therapeutic strategy from anakinra to colchicine was successful.

Pembrolizumab-induced follicular eruption and response to isotretinoin

Background: Pembrolizumab is a monoclonal antibody targeting PD-1. Folliculitis secondary to pembrolizumab has rarely been reported in the treatment of malignant melanoma. Case: A 49-year-old with a history of mild lower limb folliculitis developed metastatic malignant melanoma, and immunotherapy with pembrolizumab was initiated. Following 19 doses of pembrolizumab, a folliculocentric pustular eruption developed on the lower legs. Biopsy was consistent with folliculitis. Treatment with topical corticosteroids, high-dose prednisolone, lymecycline, clarithromycin, trimethoprim and clindamycin was unsuccessful. Pembrolizumab was stopped after 22 cycles, but the folliculitis persisted. Oral isotretinoin was required for disease control. Discussion: Drug-induced follicular eruptions have rarely been described with anti PD-1 therapy. Isotretinoin may be required to achieve remission.

O64: GENOMIC PROFILING USING CIRCULATING NUCLEIC ACIDS IN STAGE IV MELANOMA PATIENTS RECEIVING IMMUNOTHERAPY REVEALS A NOVEL GENE AMPLIFICATION LANDSCAPE AND ALLOWS FOR DETECTION OF ACTIONABLE GENE MUTATIONS

Introduction

Serial monitoring for disease progression and therapeutic efficacy at the molecular level in metastatic melanoma is hampered by a lack of reliable blood borne biomarkers. Molecular profiling of melanoma tumours is almost impractical in metastatic disease due to risks of procedure related morbidity and sampling inefficiency in representing tumour heterogeneity. Cell free DNA allows monitoring of molecular changes in melanoma over the course of immunotherapy. We investigated the utility of somatic mutation and gene amplification analyses in melanoma patients receiving immunotherapy.

Method

Cell free DNA was extracted from plasma using a QIAamp Circulating Nucleic Acid Kit (Qiagen). Pathway focused profiling of somatic mutation status was performed by ARMs PCR using QBiomarker Somatic Mutation PCR Arrays (Qiagen). Gene amplification analysis was performed by Real Time Quantitative PCR (Roche) using RT2 Profiler PCR Arrays (Qiagen).

Result

A total of twenty patients with stage IV melanoma receiving immunotherapy were enrolled in this study. The BRAF p.V600E mutation was detected in the cfDNA of 80% of BRAF positive patients. Cell free DNA was also profiled for a total of 84 genes of the cancer inflammation and immunity pathway. There was a significant difference in the copy numbers of several genes (CTLA-4, CXCL12, CXCL5, IDO1, TGFB, IFNG, IL4, PTGS2, AICDA, HLA-A, CCL4, ACKR3, TP53, MYC) between patients with progressive disease and therapeutic response (n=20, p &lt; 0.05).

Conclusion

We postulate that cell free DNA pathway focused somatic mutation and gene amplification analyses may be useful in evaluating disease progression and therapeutic response.

Take-home message

Genomic analysis of circulating nucleic acids may be useful in evaluating disease progression and therapeutic response in metastatic melanoma.

The role of tumour morphology in assigning HPV status in oropharyngeal squamous cell carcinoma

OBJECTIVES

There is no consensus on the optimal approach to human papilloma virus (HPV) testing in oropharyngeal squamous cell carcinoma (OPSCC). Our objective was to classify OPSCC as HPV positive or negative based on (1) morphology alone, (2) p16 status alone, (3) combined morphology and p16 status with additional HPV testing in discordant cases in keeping with 2012 College of American Pathologists (CAP) guidelines (combined approach), and to evaluate and compare survival outcomes.

MATERIALS AND METHODS

Retrospective review of 168 patients, 146 with OPSCC and 22 with cervical SCC of unknown primary site (SCCUP). Morphology was classified as keratinizing or non-keratinizing, p16 immunohistochemistry (IHC) performed and additional HPV DNA PCR testing undertaken in cases in which morphology and p16 status were discordant. Survival statistics were evaluated and compared for the 3 different approaches to classification.

RESULTS

On univariate analysis all 3 classification methods significantly predicted for overall survival (OS). Both p16 status and the combined approach also predicted for disease specific survival (DSS), whereas morphology fell just outside significance (p = 0.06). On multivariate analysis only the combined approach retained significance for both OS and DSS, whilst morphology was also significant for DSS.

CONCLUSIONS

Our findings confirm that tumour morphology significantly predicts for survival in OPSCC. However, we found combined tumour morphology and p16 IHC, with additional testing for discordant cases to be superior to either morphology or p16 IHC alone. Further study is required to establish the optimal testing method for HPV in OPSCC particularly in low prevalence populations.

Skin Cancer Excision Is More Efficient and Cost Effectivein a Specialist Secondary Care Service

Aim To compare the relative efficiencies of skin excisions in primary and secondary care. Methods We compared the benign: malignant ratio for specimens referred by General Practice, General Surgery and the Skin Cancer Service to the regional pathology laboratory over one month. We used cost minimization analysis to compare the relative efficiencies of the services. Results 620 excisions were received: 139 from General Practice, 118 from General Surgery and 363 from the Skin Cancer Service. The number (%) of malignant lesions was 13 (9.4%) from General Practice, 18 (15.2%) from General Surgery and 137 (37.7%) from the Skin Cancer Service. Excision was cheaper in General Practice at €84.58 as compared to €97.49 in the hospital day surgical unit. However, the cost per malignant lesion excised was €1779.80 in general practice versus €381.78 in the Skin Cancer Service. Conclusion Our results indicate that moving skin cancer treatment to General Practice may result in an excess of benign excisions and therefore be both less efficient and less cost effective.

Abstract B63: Calcium electroporation offers an effective local treatment with immunogenic cell death and the potential for systemic remission in melanoma

Electrochemotherapy is an established treatment modality in which chemotherapeutics are delivered systemically or locally in combination with local electrical pulses. Pulsing parameters are optimized to induce the reversible formation of pores in the cell membrane, leaving cells intact and healthy. Osmotic gradients during poration result in the rapid uptake of extracellular components, which results in enhanced chemotherapeutic uptake, between 5 to 2,000-fold depending on the hydrophobicity of the drug used. Complete local response rates for dermal lesions exceed 80%. Treatment is suitable for use in proximity to vasculature and offers superior cosmetic results in comparison to surgery when used in areas such as the eyelid or mouth. Recent advances have, however, been able to replace cytotoxic chemotherapeutic agents with calcium with no decrease in efficacy. The nature of cell death induced is believed to be acute, but to date has not been clearly characterized. Using Flou-4 to track the duration of elevated intracellular calcium concentrations, we have shown that elevated calcium levels persist for hours following treatment. Cell death occurs in 60-80% of cells treated in vitro within 8 hours of treatment. Cells surviving this initial insult show no detectable loss in survival or growth potential and appear otherwise unaffected. Necrotic cell death provides a significant source of damage-associated molecular patterns and may aid the generation of anticancer immune responses. Using cocultured macrophages, we have been able to show that treatment can indirectly boost cytotoxic T-cell responses via tumor-associated macrophages. The elucidation of cell death during treatment is critical for the effective optimization of clinical treatment parameters, which has hitherto been determined empirically. Other advances, such as the use of high-frequency electroporation, are transforming the clinical delivery. It is foreseeable that the requirement of surgical theaters may be avoided with the development of a pain-free treatment in the absence of cytotoxic drugs.

Note:This abstract was not presented at the conference.

Citation Format: Liam Friel Tremble, Cynthia Heffron, Patrick Forde. Calcium electroporation offers an effective local treatment with immunogenic cell death and the potential for systemic remission in melanoma [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr B63.

Association between thyroid nodule size and malignancy rate

INTRODUCTION

The diagnostic performance of ultrasound-fine needle aspiration to identify thyroid nodules harbouring malignancy remains variable. The aim of this study was to determine thyroid nodule size and cytological classification as predictors of malignancy risk.

MATERIALS AND METHODS

We conducted a retrospective cohort analysis at an academic hospital involving 499 consecutive patients who underwent thyroid surgery between 2004 and 2015.

RESULTS

A total of 503 thyroid nodules (499 patients, 84% female; mean age 50.8 years, standard deviation, SD, 15.4 years) were analysed. Of these, 19.5% were malignant. The mean (± SD) nodule size was 3.28 ± 1.63 cm and 3.27 ± 1.54 cm for benign and malignant nodules, respectively. The odds of malignancy for thyroid nodules less than 3.0 cm was similar to those for nodules of 3.0 cm or greater (0.26 compared with 0.29; p=0.77). Overall, the sensitivity and specificity of fine-needle aspiration in this cohort were 71.4% and 100%, respectively. The overall false negative rate was 5.4%. When the cut-off of 3.0 cm was used, the false negative rate in thyroid nodules less than 3.0 cm was 0% compared with 7.0% in nodules of 3.0 cm or greater. Thus, class (p<0.01) but not nodule size (p=0.49), was associated with higher malignancy risk.

CONCLUSIONS

Our results suggest that thyroid nodule size did not accurately predict the risk of thyroid malignancy irrespective of fine-needle aspiration cytology. Routine diagnostic thyroid lobectomy solely owing to thyroid nodule size of 3.0 cm or greater is currently not justified.

Natalizumab induced cutaneous sarcoidosis-like reaction

We present a case of a drug-induced sarcoidosis -like reaction (DISR) occurring following initiation of Natalizumab for multiple sclerosis. The reaction was purely cutaneous, and disappeared following drug withdrawal. We highlight this case to the practicing neurologists, with warning to be wary of a new rash on immunomodulatory therapies.

Implementation and evaluation of a new automated interactive image analysis system

OBJECTIVE

To compare automated interactive screening using the ThinPrep Imaging System with independent manual primary screening of 12,000 routine ThinPrep slides.

STUDY DESIGN

With the first 6,000 cases, the Review Scopes (RS) screening results from the 22 fields of view (FOV) only were compared to independent manual primary screening. In the next 6,000 cases, any abnormality detected in the 22 FOV resulted in full manual screening on the cytotechnologist's own microscope. Sensitivity and specificity together with their 95% CIs were calculatedfor each method.

RESULTS

In the first set of 6, 000 cases, diagnostic sensitivity and specificity of the imager were 85.19% and 96.67%, respectively. The diagnostic sensitivity and specificity of manual primary screening were 89.38% and 98.42%. This highersensitivity and specificity of manual primary screening were found to be statistically significant. The second set of 6,000 cases demonstrated no significant statistical difference in sensitivity or specificity between the sets of data.

CONCLUSION

The results from our study show that the sensitivity and specificity of the imager technology are equivalent to those of manual primary screening. The system is ideally suited to the rapid screening of negative cases, allowing increased laboratory productivity and greater throughput of cases on a daily basis.