Established and new treatment roadmaps for pleural mesothelioma: opinions of the Turkish Collaborative Group

Pleural mesothelioma (PM) is a cancer of the pleural surface, which is aggressive and may be rapidly fatal. PM is a rare cancer worldwide, but is a relatively common disease in Turkey. Asbestos exposure is the main risk factor and the most common underlying cause of the disease. There have been significant improvements in diagnoses and treatments of many malignancies; however, there are still therapeutic challenges in PM. In this review, we aimed to increase the awareness of health care professionals, oncologists, and pulmonologists by underlining the unmet needs of patients with PM and by emphasizing the need for a multidisciplinary treatment and management of PM. After reviewing the general information about PM, we further discuss the treatment options for patients with PM using immunotherapy and offer evidence for improvements in the clinical outcomes of these patients because of these newer treatment modalities.

Scrape cytology and radiological solid size correlation can be used in the intraoperative management of subsolid lung nodules

BACKGROUND

The term radiologic subsolid lung nodule (SLN) represents a heterogeneous group of non-neoplastic and neoplastic lesions. Intraoperative evaluation (IO) is often required to differentiate and diagnose. The current study aims to investigate the feasibility and reliability of scrape cytology (SC) and radiologic solid size correlation for the IO diagnosis of SLNs.

METHODS

Sixty-eight patients with SLN signs were eligible to take part in the study due to intraoperatively prepared SC slides. We managed to complete the blind radiologic solid size measurement and cytologic evaluation retrospectively. Cases were grouped into three categories based on their cytological features: Group-0 (Benign), Group-1 (mild atypical features), and Group-2 (severe atypical features/unequivocally carcinoma). IO diagnoses were given by combining the radiologic solid size and cytological findings.

RESULTS

Cytological features of Group-1 were observed in 100%, 93%, 32.5%, and 17% of the AIS, MIA, IA, and benign lesions, respectively. Cytological features of Group-2 were observed in 67.5%, and 7% of the IA and MIA, respectively. By combining cytology with radiologic solid size, 100%, 85%, 71%, and 83% of the AIS, IA, MIA, and benign lesions respectively were diagnosed correctly. Fifteen (15%) percent of the IA cases were underdiagnosed as MIA since their radiological solid sizes were less than 0.5 cm with cytological features of Group-1. Conversely, 29% of the MIA cases were overdiagnosed as IA since their radiological solid sizes were greater than 0.5 cm.

CONCLUSION

SLNs should be handled with caution in terms of IO management. SC and radiologic solid size correlation both provide a practical and tissue-protecting approach for the IO evaluation of SLNs, ensuring a high consistency between IO and definitive diagnosis.

Different Decellularization Methods in Bovine Lung Tissue Reveals Distinct Biochemical Composition, Stiffness, and Viscoelasticity in Reconstituted Hydrogels

Extracellular matrix (ECM)-derived hydrogels are in demand for use in lung tissue engineering to mimic the native microenvironment of cells in vitro. Decellularization of native tissues has been pursued for preserving organotypic ECM while eliminating cellular content and reconstitution into scaffolds which allows re-cellularization for modeling homeostasis, regeneration, or diseases. Achieving mechanical stability and understanding the effects of the decellularization process on mechanical parameters of the reconstituted ECM hydrogels present a challenge in the field. Stiffness and viscoelasticity are important characteristics of tissue mechanics that regulate crucial cellular processes and their in vitro representation in engineered models is a current aspiration. The effect of decellularization on viscoelastic properties of resulting ECM hydrogels has not yet been addressed. The aim of this study was to establish bovine lung tissue decellularization for the first time via pursuing four different protocols and characterization of reconstituted decellularized lung ECM hydrogels for biochemical and mechanical properties. Our data reveal that bovine lungs provide a reproducible alternative to human lungs for disease modeling with optimal retention of ECM components upon decellularization. We demonstrate that the decellularization method significantly affects ECM content, stiffness, and viscoelastic properties of resulting hydrogels. Lastly, we examined the impact of these aspects on viability, morphology, and growth of lung cancer cells, healthy bronchial epithelial cells, and patient-derived lung organoids.

Hypersensitivity reactions to COVID-19 vaccines: a case of Eosinophilic pneumonia following Sinovac/CoronaVac vaccination

Summary

Hypersensitivity reactions has been reported with COVID-19 vaccines. Acute eosinophilic pneumonia has not been reported yet after Sinovac/CoronaVac vaccine. A 73-year-old woman presented with maculopapular rash, cough and dyspnea following Sinovac/CoronaVac injection. The complete blood count (CBC) indicated eosinophilia and further evaluation of the eosinophilia with CT and bronchoscopy confirmed a diagnosis of acute eosinophilic pneumonia. After methylprednisolone therapy, her rash resolved with marked improvement of the dyspnea. She is still on treatment and on the follow up period, we plan to continue steroid treatment at least 3 months.

KRAS signaling in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) arises from mesothelial cells lining the pleural cavity of asbestos‐exposed individuals and rapidly leads to death. MPM harbors loss‐of‐function mutations in BAP1, NF2, CDKN2A, and TP53, but isolated deletion of these genes alone in mice does not cause MPM and mouse models of the disease are sparse. Here, we show that a proportion of human MPM harbor point mutations, copy number alterations, and overexpression of KRAS with or without TP53 changes. These are likely pathogenic, since ectopic expression of mutant KRAS^G12D in the pleural mesothelium of conditional mice causes epithelioid MPM and cooperates with TP53 deletion to drive a more aggressive disease form with biphasic features and pleural effusions. Murine MPM cell lines derived from these tumors carry the initiating KRAS^G12D lesions, secondary Bap1 alterations, and human MPM‐like gene expression profiles. Moreover, they are transplantable and actionable by KRAS inhibition. Our results indicate that KRAS alterations alone or in accomplice with TP53 alterations likely play an important and underestimated role in a proportion of patients with MPM, which warrants further exploration.

Efficiency of Cytology Samples for PD-L1 Evaluation and Comparison with Tissue Samples

OBJECTIVE

Lung cancer is the leading cause of cancer-related death. PD-L1 blockers have become a first-line option for advanced non-small cell lung cancer (NSCLC) patients. Guidelines require the assessment of PD-L1 expression by immunohistochemistry. Although tissue samples are widely used, cytologic samples could be an alternative. In this study, we compared cytologic samples with tissue samples for PD-L1 evaluation in NSCLC cases.

MATERIAL AND METHOD

Koç University Hospital, Department of Pathology Laboratory Information System was scanned for all PD-L1 tests performed on NSCLC cases, either on tissue samples or cell blocks. The type of the biopsy/aspiration procedure, the tumor type, patient demographics, and the percentage of PD-L1 positive tumor cells were recorded. A total of 73 tissue samples and 49 cell blocks were found to be eligible for the study.

RESULTS

The PD-L1 positivity score was at least 1% in 44 of 73 samples of the tissue group and 19 of 49 samples of the cell block group. Tissue samples showed significantly higher positivity compared to the cell blocks (p=0.020). Comparing the frequency of cases with ≥50% positivity showed no statistically significant difference. A comparison of PD-L1 positivity rates of only the small biopsies and cell blocks also showed no significant difference.

CONCLUSION

Although they harbor a limited number of tumor cells, cell blocks prepared from cytologic samples are good alternatives for PD-L1 testing. However, large resections should be used for PD-L1 evaluation whenever possible since even 1% positivity may affect the treatment decision.

Pitfalls in the Cytological Assessment of Thyroid Nodules

Fine needle aspiration of thyroid has been used for years in a multidisciplinary approach, to diagnose different entities, in preventing over or under treatment of thyroid nodules. The widespread use of this methodology can be confirmed if "thyroid fine needle aspiration" is searched on PubMed, which results in over 5000 papers. In this manuscript, we aimed to focus on pitfalls in the evaluation of thyroid aspirations, covering cystic, inflammatory lesions, follicular lesions, oncocytic lesions, papillary carcinoma, and medullary carcinoma of thyroid.

Primary sebaceous carcinoma of the lacrimal gland

Primary sebaceous carcinoma is an exceptionally rare tumor of the lacrimal gland and less than 10 cases have been so far published in the literature. Two adult patients aged 38 and 81 years, respectively, who suffered unilateral painful massive swelling of the lacrimal gland are described. The disease in the first patient initially manifested as ipsilateral parotid gland metastasis and the primary tumor could be detected 3 months later. Both tumors were rock hard and fixed on palpation, caused partial upper eyelid ptosis, displaced the globe anteromedially and impaired ocular motility. Magnetic resonance imaging studies showed mostly homogeneous, well-delineated and moderately contrast-enhancing lacrimal gland fossa tumors without bone destruction. The management consisted of incisional biopsy for the diagnosis, immediately followed by exenteration. The younger patient further underwent radical neck dissection, parotidectomy and orbital and neck radiotherapy, which provided him a 2-year disease-free survival. Histopathological examination showed poorly differentiated sebaceous carcinoma destructing completely the lacrimal gland with predominantly comedo pattern. Despite its rarity and lack of specific clinical and imaging signs, sebaceous carcinoma should be considered in rapidly evolving painful and hard lacrimal gland fossa tumors. Also noteworthy is the early propensity of this tumor to spread to regional draining lymph nodes and the parotid gland in particular.

Expression of glutathione-S-transferases isoenzymes and p53 in exfoliated human bladder cancer cells

OBJECTIVES

This study investigates the usefulness of glutathione-S-transferases (GST) isoenzymes and p53 immunostaining as a marker of malignancy in urinary cytology, and evaluates their potential effect in increasing diagnostic accuracy in a series of urine cytologic samples. They are also correlated with cytopathology diagnosis and histopathologic diagnosis.

MATERIALS AND METHODS

In this study, the slides from 124 bladder carcinoma patients prepared by the cytocentrifugation method were observed. The cytomorphologic properties of these cancer cells were determined. Moreover, the immunocytochemical distributions of GST alpha (GSTA), pi (GSTP), mu (GSTM4), theta (GSTT1) isoenzymes and p53 protein were studied for the patients.

RESULTS

The urothelial cancer cells had small cytoplasm and rough nuclear membrane. The chromatin granules were heterogeneously distributed in each malignant cell's nucleus. There was a pleomorphism of the malignant cells' nuclei. According to immunocytopathologic observations, the urothelial cancer cells had stronger staining intensity than the benign cells had in 48% of cases for GSTA, 46% of cases for GSTP, 38% of cases for GSTM4, and 42% of cases for GSTT1. For all papillary cases, the malignant cells were stained negative, while the benign cells were positive. For 83% of patients, the malignant cells were stained positive for p53. There was a significant difference in GSTA (P = 0.006), GSTT1 (P = 0.004), GSTP (P = 0.000) and p53 (P = 0.000) expressions for benign cells whereas, a non-statistical difference in the malignant cells for GSTA, GSTT1, GSTP, GSTM4, and p53 expressions (P > 0.05).

CONCLUSIONS

GST isoenzymes and p53 immunostaining were not found to be markers of malignancy in urinary cytology.