Impact of PD-L1 Protein Expression on Renal Cell Carcinoma Histo-differentiation

BACKGROUND/AIM

Renal cell carcinoma (RCC) comprises a variety of pathological entities. Many RCCs are aggressive, demanding efficient targeted and immunetherapeutic strategies. Programmed cell death ligand-1 (PD-L1) is expressed mainly in hematopoietic cells and also in epithelial cells. The aim of this study was to correlate PD-L1 protein expression in a series of RCC tissues with their histo-pathological features.

MATERIALS AND METHODS

One hundred (n=100) archival, formalin-fixed and paraffin-embedded RCC tissue specimens were analysed by immunohistochemistry. Conventional tumor proportion score (TPS) qualitative assay was applied for evaluating protein expression levels.

RESULTS

Based on the TPS evaluation, 8 (8%) cases were characterized as positive, and the rest of them (n=92; 92%) as negative. A progressive increase in PD-L1 positivity was significantly associated with the differentiation grade of the examined malignancies (p=0.001).

CONCLUSION

Although PD-L1 over-expression is detected in low rates in RCCs, its correlation with differentiation grade should be considered as a factor for discriminating sub-groups of patients with specific histo-pathological features eligible for targeted anti-PD-L1 immunotherapy strategies.

Site-specific use of molecular markers could be a promising prognostic tool in colorectal cancer

Proximal and distal colorectal carcinomas (CRCs) are generally considered as genetically and clinicopathologically distinct disease entities. Tumor location has been proposed as an additional prognostic indicator and -more recently- as a factor with significant influence on the prognostic value of particular molecular markers and/or combination of markers (KRAS, MSI, APC/MSI), allowing the discrimination of specific disease subsets with considerably disparate outcome and the identification of high risk cases. This article examines the clinical importance of particular recent proposals on this specific issue. Their strengths and limitations, as well as issues requiring further elucidation and practical problems hampering their clinical implementation are briefly discussed. Moreover, some suggestions intending to improve research methodology on this specific theme and to render the clinical use of this novel approach more effective and feasible, are presented. Hopefully, the assessment of certain molecular markers in a site-specific fashion could be another step towards personalized management of CRC, improving and complementing the molecular classification of the disease.

Cytological Features of the Large Cell Variant of Small Cell Ovarian Carcinoma in Young Patients with Hypercalcemia: Histological Findings and Review of the Literature

OBJECTIVE

To present the cytological features of a very rare and lethal ovarian neoplasm occurring in the young.

STUDY DESIGN

We reviewed the cytological findings as they presented in touch imprints obtained from an ovarian mass sent to our department for frozen section investigation.

RESULTS

Smears were highly cellular. The cells were of intermediate size with a moderate amount of microvacuolated, pale, or eosinophilic cytoplasm with indistinct cell borders. The nuclei were of round or oval shape with mild to moderate atypia and indistinct nucleoli.

CONCLUSIONS

The diagnosis of small cell carcinoma of the ovary can be challenging even histologically. Cytology can be an invaluable adjunct to hematoxylin-eosin sections both pre- or intraoperatively. Although it is a very rare occurrence and cytological results are almost absent in the literature, our case can make cytopathologists more acquainted with the cytological features of this rare tumor entity especially in association with a characteristic clinical profile. Furthermore, the cytological features of small cell carcinoma of the ovary, large cell variant, have only rarely been described in the literature.

Extragastrointestinal stromal tumour of the lesser omentum: A case report and literature review

•

EGISTs are very rare mesenchymal tumours which originate from cells outside the gastrointestinal tract and tend to have an aggressive biological behaviour.

•

There have been only a few previous reports of EGISTs arising in the lesser omentum.

•

Complete surgical resection is the most effective treatment associated with the use of imatinib in the presence of adverse prognostic factors.

Introduction

Extragastrointestinal stromal tumours (EGISTs) are very uncommon compared to their gastrointestinal counterparts. Most of them originate from the intestinal mesentery and the omentum.

Case report

A 70 year-old Caucasian woman presented with a bulky abdominal mass which on laparotomy was found to originate from the lesser omentum and was completely resected. Histological examination revealed spindle cells with severe pleomorphism and high mitotic activity. Immunohistochemically, the tumour cells showed strong positivity for c-kit (CD117), DOG-1 and human haematopoietic progenitor cell antigen (CD34). An exon 11 deleterious mutation was identified and thus regular dosing of 400 mg imatinib mesylate was initiated.

Discussion

There have been only a few previous reports of EGISTs arising in the lesser omentum. Although EGISTs seem to have morphological and immunohistochemical similarities with GISTs, their pathogenesis, incidence, genetic background and prognosis are not completely known because they are extremely rare. It is strongly believed that such tumours originate from cells, which have similar pathological characteristics and biological behaviour as the intestinal cells of Cajal. In most series of EGISTs, a female predominance, a greater size and a higher mitotic index than GISTs were observed.

Conclusion

EGISTs are very rare mesenchymal tumours which originate from cells outside the gastrointestinal tract and tend to have a more aggressive biological behaviour than their GI counterparts. Complete surgical resection is the most effective treatment associated with the use of imatinib in the presence of adverse prognostic factors. In any case a strict follow-up is necessary due to high recurrence rates.