Case Report: Durable therapy response to Osimertinib in rare EGFR Exon 18 mutated NSCLC.

Up to 20% of all non-small cell lung cancer patients harbor tumor specific driver mutations that are effectively treated with tyrosine kinase inhibitors. However, for the rare EGFR deletion-insertion mutation of exon 18, there is very little evidence regarding the effectiveness of tyrosine kinase inhibitors. A particular challenge for clinicians in applying tyrosine kinase inhibitors is not only diagnosing a mutation but also interpreting rare mutations with unclear therapeutic significance. Thus, we present the case of a 65-year-old Caucasian male lung adenocarcinoma patient with an EGFR Exon 18 p.Glu709_Thr710delinsAsp mutation of uncertain therapeutic relevance. This patient initially received two cycles of standard platinum-based chemotherapy without any therapeutic response. After administration of Osimertinib as second line therapy, the patient showed a lasting partial remission for 12 months. Therapy related toxicities were limited to mild thrombocytopenia, which ceased after dose reduction of Osimertinib. To our knowledge, this is the first report of effective treatment of this particular mutation with Osimertinib. Hence, we would like to discuss Osimertinib as a viable treatment option in EGFR Exon 18 p.Glu709_Thr710delinsAsp mutated lung adenocarcinoma.

Deep-learning based classification of a tumor marker for prognosis on Hodgkin's disease.

PURPOSE: Hodgkin's disease is a common malignant disorder in adolescent patients. Although most patients are cured, approximately 10%-15% of patients experience a relapse or have resistant disease. Furthermore, there are no definitive molecular predictors for early identification of patients at high risk of treatment failure to first line therapy. The aim of this study was to evaluate the deep learning-based classifier model of medical image classification to predict clinical outcome that may help in appropriate therapeutic decisions. METHODS: Eighty-three FFPE biopsy specimens from patients with Hodgkin's disease were stratified according to the patient's qPET scores, stained with picrosirius red dye and digitalized by whole slide image scanning. The resulting whole slide images were cut into tiles and annotated by two classes based on the collagen fibers' degree of coloring with picrosirius red. The neural network (YOLOv4) was then trained with the annotated data. Training was performed with 30 cases. Prognostic power of the weakly stained picrosirius red fibers was evaluated with 53 cases. The same neural network was trained with MMP9 stained tissue slides from the same cases and the quantification results were compared with the variant from the picrosirius red cases. RESULTS: There was a weak monotonically increasing relationship by parametric ANOVA between the qPET groups and the percentages of weakly stained fibers (p = .0185). The qPET-positive cases showed an average of 18% of weakly stained fibers, and the qPET-negative cases 10%-14%. Detection performance showed an AUC of 0.79. CONCLUSIONS: Picrosirius red shows distinct associations as a prognostic metric candidate of disease progression in Hodgkin's disease cases using whole slide images but not sufficiently as a prognostic device.

Mutation patterns in recurrent and/or metastatic oropharyngeal squamous cell carcinomas in relation to human papillomavirus status.

Patients with HPV-driven (HPV+) oropharyngeal squamous cell carcinoma (OPSCC) have a significantly improved overall survival compared to patients with HPV-negative (HPV-) OPSCC. Nevertheless, 13%-25% of patients with HPV+OPSCC develop local/distant recurrence (LDR) and have a course of disease similar to HPV-OPSCC. We hypothesize that HPV+OPSCCs of patients with LDR have a mutation frequency and pattern similar to HPV-OPSCCs, which is associated with severe outcome. We performed targeted next-generation sequencing using a customized gene panel and compared data from 56 matched HPV+and HPV-OPSCC of patients with/without LDR regarding protein-altering variants. Despite improved overall survival of patients with HPV+OPSCC, those who develop LDR show a strongly reduced survival rate that is similar or even worse compared to HPV-OPSCC patients. Overall, the number of mutations was similar in OPSCC of patients with and without LDR. In total and with respect to TP53, HPV-OPSCC had significantly more protein-altering mutations than HPV+OPSCC. The number of mutations was similar in HPV-OPSCC of patients with and without LDR with the exception of FAT1, which was mutated more frequently in patients without LDR. In HPV+OPSCC, HRAS, PIK3R1, STK11 and TP63 were more frequently mutated in patients with LDR compared to patients without. HPV+OPSCC of patients with LDR have a similar mutation pattern as HPV-OPSCC, except TP53, which was mutated to a significantly lower extent. In conclusion, HPV-and HPV+OPSCC with LDR have similar mutation counts in the analyzed genes. We suspect that the number of mutations is not causal for disease progression, rather specific mutations could be important.

Genetic alterations in human papillomavirus-associated oropharyngeal squamous cell carcinoma of patients with treatment failure.

OBJECTIVES: Despite improved survival rates of patients with HPV-associated OPSCC, a subset has distant metastasis or develops local recurrence during follow-up. To investigate potential underlying genetic alterations, we analyzed patients with HPV-driven OPSCC who suffered from recurrence in comparison to matching pairs with successful tumor control. MATERIALS AND METHODS: We performed chromosomal copy number analyses and targeted next generation sequencing using a custom panel comprising genes that are frequently mutated in HPV-associated OPSCC. RESULTS: Specific differences regarding chromosomal aberrations were not observed between both groups. In HPV-driven OPSCC from patients with recurrence we found higher mutation rates compared to patients with successful tumor control. Especially mutation rates of HRAS (p ≤ 0.05) PIK3R1, STK11 and TP63 (p ≤ 0.1 each) were statistically significant or trending towards significance. The respective genes can be linked to transcription factors and signaling pathways involved in cell cycle regulation, proliferation and survival. Additionally, combinations of alterations were observed on chromosomes 16 and 19, which might also influence outcome. CONCLUSION: Patients with HPV-driven OPSCC who develop recurrence or have metastasis may be defined by genetic alterations that might be responsible for poor outcome after standard therapy. This might be of importance for stratification in future de-escalation and targeted therapy.

The wide spectrum of POT1 gene variants correlates with multiple cancer types.

The POT1 protein binds and protects telomeres. Germline variants in the POT1 gene have recently been shown to be associated with risk of developing tumors in different tissues such as familial chronic lymphocytic leukemia, colorectal, glioma and melanoma tumors. Recently, we uncovered a variant in the POT1 gene (p.R117C) as causative of familial cardiac angiosarcomas (CAS) in Li-Fraumeni-like (LFL) syndrome families. Our in silico studies predicted that this protein had lost the ability to interact with TPP1 and single-stranded DNA. In vitro studies corroborated this prediction and showed that this lack of function leads to abnormally long telomeres. To better understand the POT1 gene and its role with tumorigenesis, we extended the study to LFL (with and without members affected with angiosarcomas (AS)) and sporadic AS and cardiac sarcomas. We found POT1 variants in the 20% of the families with members affected with AS and 10% of sporadic AS and sarcomas. In silico studies predicted that these new variants were damaging in the same manner as previously described for the POT1 p.R117C variants. The wide spectrum of variants in the POT1 gene leading to tumorigenesis in different tissues demonstrates its general importance. Study of the POT1 gene should be considered as routine diagnostic in these cancers.

Genomic EWS-FLI1 fusion sequences in Ewing sarcoma resemble breakpoint characteristics of immature lymphoid malignancies.

Chromosomal translocations between the EWS gene and members of the ETS gene family are characteristic molecular features of the Ewing sarcoma. The most common translocation t(11;22)(q24;q12) fuses the EWS gene to FLI1, and is present in 85-90% of Ewing sarcomas. In the present study, a specifically designed multiplex long-range PCR assay was applied to amplify genomic EWS-FLI1 fusion sites from as little as 100 ng template DNA. Characterization of the EWS-FLI1 fusion sites of 42 pediatric and young adult Ewing sarcoma patients and seven cell lines revealed a clustering in the 5' region of the EWS-breakpoint cluster region (BCR), in contrast to random distribution of breakpoints in the FLI1-BCR. No association of breakpoints with various recombination-inducing sequence motifs was identified. The occurrence of small deletions and duplications at the genomic junction is characteristic of involvement of the non-homologous end-joining (NHEJ) repair system, similar to findings at chromosomal breakpoints in pediatric leukemia and lymphoma.

Promoter methylation of cyclin A1 is associated with human papillomavirus 16 induced head and neck squamous cell carcinoma independently of p53 mutation.

Aberrant promoter methylation of specific genes and infection with human papillomavirus 16 (HPV16) are known risk factors for the development of Head and Neck Squamous Cell Carcinoma (HNSCC). Little knowledge exists on the interaction of HPV16 infection and promoter methylation in HNSCC. The promoter methylation status of 12 genes (TIMP3, CDH1, CDKN2A, DAPK1, transcription factor 21 (TCF21), CD44, MLH1, MGMT, RASSF1, cyclin A1 (CCNA1), LARS2, and CEBPA) was evaluated by methylation-specific polymerase chain reaction in 55 primary HNSCC and 31 controls. The results were correlated with HPV16 status and clinicopathological characteristics. CCNA1 and p53 protein expression were additionally determined by immunohistochemistry and compared with p53 mutation status. Methylation of DAPK1 (P = 0.043), CCNA1 (P = 0.016) and TCF21 (P = 0.0005) was significantly more present in HNSCC than in controls. The genes TIMP3 (P = 0.018) and CCNA1 (P = 0.015) showed higher methylation frequency in HPV16 positive HNSCC compared to HPV16 negative tumors. CCNA1 methylation did not correlate with CCNA1 protein expression and p53 mutation, respectively. Methylation of TCF21 was associated with higher age (P = 0.044) and nicotine abuse (P = 0.035). Methylation of CCNA1 was significantly more present in females (P = 0.003). Methylation of TCF21 and CCNA1 are important risk factors for HNSCC development. CCNA1 methylation may play a crucial role in HPV16-induced carcinogenesis of HNSCC independently of p53.