Disruptive and Truncating TP53 Mutations Are Associated with African-Ancestry and Worse Prognosis in Brazilian Patients with Lung Adenocarcinoma.

INTRODUCTION: TP53 is the most frequently mutated gene in lung tumors, but its prognostic role in admixed populations, such as Brazilians, remains unclear. In this study, we aimed to evaluate the frequency and clinicopathological impact of TP53 mutations in non-small cell lung cancer (NSCLC) patients in Brazil. METHODS: We analyzed 446 NSCLC patients from Barretos Cancer Hospital. TP53 mutational status was evaluated through targeted next-generation sequencing (NGS) and the variants were biologically classified as disruptive/nondisruptive and as truncating/nontruncating. We also assessed genetic ancestry using 46 ancestry-informative markers. Analysis of lung adenocarcinomas from the cBioportal dataset was performed. We further examined associations of TP53 mutations with patients' clinicopathological features. RESULTS: TP53 mutations were detected in 64.3% (n = 287/446) of NSCLC cases, with a prevalence of 60.4% (n = 221/366) in lung adenocarcinomas. TP53 mutations were associated with brain metastasis at diagnosis, tobacco consumption, and higher African ancestry. Disruptive and truncating mutations were associated with a younger age at diagnosis. Additionally, cBioportal dataset revealed that TP53 mutations were associated with younger age and Black skin color. Patients harboring disruptive/truncating TP53 mutations had worse overall survival than nondisruptive/nontruncating and wild-type patients. CONCLUSION: TP53 mutations are common in Brazilian lung adenocarcinomas, and their biological characterization as disruptive and truncating mutations is associated with African ancestry and shorter overall survival.

Quality Assessment of Cryopreserved Human Biological Samples from the Biobank of Barretos Cancer Hospital.

Background: Biobanks process, store, and supply biological materials for research. Preanalytical factors, especially storage time and temperature, must be controlled and standardized at all stages when handling biospecimen samples, especially because the literature reports highly contradictory optimal parameters. As large-sample studies are required to better understand the influence of time and temperature on cryopreserved samples' quality for genomic research, this study evaluated the integrity and quality of cryopreserved samples stored for up to 9 years at the biobank of Barretos Cancer Hospital, one of the largest biobanks in Latin America. Methods: We randomly selected 447 samples with tumor tissue paired with buffy coat or peripheral blood mononuclear cells (PBMCs) that were stored from 2008 to 2016. The genetic material quality was evaluated based on RNA integrity (RIN) and DNA integrity (DIN) ≥7, which indicated undegraded samples, and compared with storage time, which means that for DNA storage time, samples <8.1 and ≥8.1 years and for RNA <4.5 and ≥4.5 were used. Results: A total of 190 tumor tissues were eligible for DNA and RNA extraction. Those stored for 8 years had lower DIN (68%) than those stored for a shorter period (92%). A similar pattern, based on storage time (<8.1 and ≥8.1 years), was observed in the buffy coat (74% and 95%, respectively) and PBMCs (54% and 96%, respectively). For RNA extracted from tumor tissues, we observed lower RIN in samples stored for 4.5 years (17%) than in samples stored for a shorter period (45%). Buffy coat and PBMC samples stored at -30°C exhibited greater degradation (26%) than those stored at -80°C (1%). The DIN (p = 0.15) and RNA (p = 0.18) were unrelated to topography type. Conclusion: The temperature, particularly cryopreservation methodology, and storage time were the main factors that affected nucleic acid integrity, especially RNA, during cryopreservation of biospecimens.

ERBB2 exon 20 insertions are rare in Brazilian non-small cell lung cancer.

ERBB2 exon 20 insertions may impact the clinical management of lung cancer patients. However, the frequency of ERBB2 exon 20 insertions in lung cancer patients in Brazil is scarce. Here, we analyzed 722 Brazilian non-small cell lung cancer (NSCLC) patients from Barretos Cancer Hospital that were indicated to require routine lung cancer molecular testing. ERBB2 exon 20 insertions were evaluated by a targeted panel using next-generation sequencing (NGS). Clinicopathological and molecular data were collected from patient medical records. Among the 722 NSCLC patients, 85.2% had lung adenocarcinomas, 53.9% were male, 66.8% were quitter or current smokers, and 63.2% were diagnosed at an advanced stage of the disease. We identified 0.8% (6/722) of patients who harbored the insertion p.(Tyr772_Ala775dup) at exon 20 of the ERBB2 gene. All ERBB2 mutated patients were diagnosed with lung adenocarcinoma, were never smokers, and wild-type for EGFR, KRAS, and ALK hotspot alterations. Less than 1% of Brazilian NSCLC patients harbor ERBB2 exon 20 insertions, yet they could benefit in future from the new drugs in development.

Microsatellite Instability Is Rare in the Admixed Brazilian Population of Non-Small Cell Lung Cancer: A Cohort of 526 Cases.

BACKGROUND: Microsatellite instability (MSI) in non-small cell lung cancer (NSCLC) is uncommon; however, most studies refer to European and Asian populations. There are currently no data on MSI frequency in highly admixed populations, such as the one represented by Brazilian NSCLC patients. AIM: This study aimed to evaluate the frequency of MSI in Brazilian NSCLC patients. METHODS: We evaluated 526 patients diagnosed with NSCLC at the Barretos Cancer Hospital (Brazil). The molecular MSI evaluation was performed using a hexa-plex marker panel by polymerase chain reaction followed by fragment analysis. The mutation profile of MSI-positive cases was performed using next-generation sequencing. RESULTS: Only 1 patient was MSI positive (0.19%). This patient was a female, white, and active smoker, and she was diagnosed with clinical stage IV lung adenocarcinoma at 75 years old. The molecular profile exhibited 4 Tumor Protein p53 (TP53) mutations and the absence of actionable mutations in the Epidermal Growth Factor Receptor (EGFR), Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS), or V-Raf Murine Sarcoma Viral Oncogene Homolog B1 (BRAF) genes. CONCLUSIONS: The frequency of MSI in Brazilian NSCLC patients is equally rare, a finding that is consistent with the current literature based on other populations such as Europeans, North Americans, and Asians.

PD-L1 expression by Tumor Proportion Score (TPS) and Combined Positive Score (CPS) are similar in non-small cell lung cancer (NSCLC).

BACKGROUND: For non-small cell lung cancer (NSCLC) the most used method for analysing programmed cell death ligand 1 (PD-L1) expression is the Tumor Proportion Score (TPS). Nevertheless, for other tumour types, the Combined Positive Score (CPS) has been the method of choice. AIM: Evaluate and compare the predictive value of both CPS and TPS as predictors of immunotherapy response in NSCLC, and to evaluate the agreement intra-observer between both methods and inter-observer between two expert lung pathologists. METHODS: 56 NSCLC patients who were treated with anti-programmed cell death 1 (PD-1)/PD-L1 therapy were included. Two pathologists evaluated all cases independently, considering the sample's adequacy for analysis, and the PD-L1 expression by TPS and CPS. RESULTS: The Kappa coefficient for adequacy was 0.82 (95% CI 0.67 to 0.97). There was a high agreement between TPS and CPS and a high agreement between pathologists concerning the two methods. The Kappa coefficient between TPS and CPS was 0.85 for both pathologists, and between pathologists was 0.94 and 0.93 for TPS and CPS, respectively. CONCLUSIONS: Both methods proved to be equally predictive of response to anti-PD-1/PD-L1 therapy. There was both a high intra-observer agreement between the two methods and a high inter-observer agreement between pathologists. This study suggests that CPS could also be used in a routine setting for immunotherapy decision in NSCLC.

Odontogenic Carcinoma With Dentinoid in Long-Term Follow-up With 2 Recurrences.

Dentinoid has been mentioned as a frequent component in several types of benign odontogenic tumors; however, there are some other very rare dentinoid-producing odontogenic tumors that have been described, which are not recognized in the current World Health Organization Histological Classification of Odontogenic Tumours. In this context, we report an unusual malignant odontogenic tumor containing dentinoid located in the left maxilla of a 41-year-old man. The lesion was initially diagnosed and treated as a cemento-ossifying fibroma. After 7 years, a tumor was noted at the same location and was diagnosed as pleomorphic adenoma. The patient developed a new lesion 2 years later. Histological features included an epithelial proliferation of basaloid and clear cells, some with peripheral palisading, which were scattered both in a fibrous stroma and within an amorphous eosinophilic dentinoid product. Because of doubts about the first 2 diagnoses and the current situation, all histopathological slides were reviewed in our service as a consultation case, and the findings were consistent with the diagnosis of an odontogenic carcinoma with dentinoid. Immunohistochemical analysis was performed and an ultrastructural study by scanning electronic microscopy and energy-dispersive X-ray microanalysis was made to characterize dentinoid material. After 1 year of follow-up, the patient is alive and free of the disease. This case highlights the wide variability regarding cytological evidence of malignancy, and adds a new case of odontogenic carcinoma with dentinoid, which represents a distinct entity with locally aggressive behavior and should be considered be included in a future World Health Organization Histological Classification of Tumours.

Hotspot TERT promoter mutations are rare events in testicular germ cell tumors.

The abnormal activation of telomerase, codified by the telomerase reverse transcriptase (TERT) gene, is related to one of cancer hallmarks. Hotspot somatic mutations in the promoter region of TERT, specifically the c.-124:C>T and c.-146:C>T, were recently identified in a range of human cancers and have been associated with a more aggressive behavior. Testicular germ cell tumors frequently exhibit a good prognosis; however, the development of refractory disease is still a clinical challenge. In this study, we aim to evaluate for the first time the presence of the hotspot telomerase reverse transcriptase gene promoter mutations in testicular germ cell tumors. A series of 150 testicular germ cell tumor cases and four germ cell tumor cell lines were evaluated by PCR followed by direct Sanger sequencing and correlated with patient's clinical pathological features. Additionally, we genotyped the telomerase reverse transcriptase gene promoter single nucleotide polymorphism rs2853669 (T>C) located at -245 position. We observed the presence of the TERT promoter mutation in four patients, one exhibited the c.-124:C>T and three the c.-146:C>T. No association between TERT mutation status and clinicopathological features could be identified. The analysis of the rs2853669 showed that variant C was present in 22.8 % of the cases. In conclusion, we showed for the first time that TERT promoter mutations occur in a small subset (~3 %) of testicular germ cell tumors.