What Does Atypical Chronic Lymphocytic Leukemia Really Mean? A Retrospective Morphological and Immunophenotypic Study.

Atypical chronic lymphocytic leukemia (CLL) is still defined according to morphological criteria. However, deviance from the typical surface immunological profile suggests an atypical immunological-based CLL. A large cohort of patients with CLL was retrospectively evaluated aiming at assessing morphological (FAB criteria), immunophenotypical (two or more discordances from the typical profile), and clinical-biological features of atypical CLL. Compared to typical cases, morphologically atypical CLL showed a greater percentage of unmutated IgVH and CD38 positivity, and a higher expression of CD20. Immunophenotypically atypical CLL was characterized by more advanced clinical stages, higher expression of CD20, higher rate of FMC7, CD79b and CD49d positivity, and by an intermediate-high expression of membrane surface immunoglobulin, compared to typical cases. When patients were categorized based on immunophenotypic and morphologic concordance or discordance, no difference emerged. Finally, morphological features better discriminated patients' prognosis in terms of time-to-first treatment, while concordant atypical cases showed overall a worse prognosis. Discordant cases by immunophenotype and/or morphology did not identify specific prognostic groups. Whether-in the era of molecular markers used as prognostic indicators-it does make sense to focus on morphology and immunophenotype features in CLL is still matter of debate needing further research.

Immunotherapy in Penile Squamous Cell Carcinoma: Present or Future? Multi-Target Analysis of Programmed Cell Death Ligand 1 Expression and Microsatellite Instability.

Background: Penile cancer (PC) is an extremely rare malignancy, and the patients at advanced stages have currently limited treatment options with disappointing results. Immune checkpoint inhibitors anti-programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) are currently changing the treatment of several tumors. Furthermore, the microsatellite instability (MSI) and the deficient mismatch repair system (dMMR) proteins represent predictive biomarkers for response to immune checkpoint therapy. Until present, few data have been reported related to PD-L1 expression and MSI in PC. The main aim of our study was the evaluation of PD-L1 expression in tumor cells (TCs) and tumor-infiltrating lymphocytes (TILs) in immune cells and the analysis of dMMR/MSI status in a large series of PCs. Methods: A series of 72 PC, including 65 usual squamous cell carcinoma (USCC), 1 verrucous, 4 basaloid, 1 warty, and 1 mixed (warty-basaloid), was collected. Immunohistochemistry (IHC) was performed to assess PD-L1 expression using two different anti-PD-L1 antibodies (clone SP263 and SP142 Ventana) and MMR proteins expression using anti-MLH1, anti-PMS2, anti-MSH2, and anti-MSH6 antibodies. PCR analysis was performed for the detection of MSI status. Results: Of the 72 PC cases analyzed by IHC, 45 (62.5%) cases were TC positive and 57 (79%) cases were combined positive score (CPS) using PDL1 SP263. In our cohort, TILs were present in 62 out of 72 cases (86.1%), 47 (75.8%) out of 62 cases showed positivity to PDL1 clone SP142. In our series, 59 cases (82%) had pMMR, 12 cases (16.7%) had lo-paMMR, and only 1 case (1.3%) had MMR. PCR results showed that only one case lo-paMMR was MSI-H, and the case dMMR by IHC not confirmed MSI status. Conclusion: Our findings showed that PD-L1 expression and MSI status represent frequent biological events in this tumor suggesting a rationale for a new frontier in the treatment of patients with PC based on the immune checkpoint inhibitors.

Discrepancy of p16 immunohistochemical expression and HPV RNA in penile cancer. A multiplex in situ hybridization/immunohistochemistry approach study.

BACKGROUND: The high-risk human papillomavirus (HPV) infection represents one of the main etiologic pathways of penile carcinogenesis in approximately 30-50 % of cases. Several techniques for the detection of HPV are currently available including Polymerase chain reaction-based techniques, DNA and RNA in situ hybridization (ISH), p16 immunohistochemistry (IHC). The multiplex HPV RNA ISH/p16 IHC is a novel technique for the simultaneous detection of HPV E6/E7 transcripts and p16INK4a overexpression on the same slide in a single assay. The main aim of this study was to evaluate the discrepancy of p16 IHC expression relatively to HPV RNA ISH in penile cancer tissue. METHODS: We collected a series of 60 PCs. HPV has been analysed through the RNA ISH, p16 IHC and the multiplex HPV RNA ISH/p16 IHC. RESULTS: The multiplex HPV RNA ISH /p16 IHC results in the series were in complete agreement with the previous results obtained through the classic p16 IHC and HPV RNA scope carried out on two different slides. The multiplex HPV RNA ISH /p16 IHC showed that HPV positivity in our series is more frequently in usual squamous cell carcinoma than in special histotypes (19 out of 60 - 15 %- versus 6 out of 60 - 10 %-), in high-grade than in moderate/low grade carcinomas (6 out of 60 - 10 %- versus 4 out of 60 - 6.7 %-). In addition, our data revealed that in 5 out of 20 cases with p16 high intensity expression is not associated with HPV RNA ISH positivity. CONCLUSIONS: Our findings emphasize that the use of p16 as a surrogate of HPV positivity was unsuccessful in approximatively 8 % of cases analysed in our series. Indeed, p16 IHC showed a sensitivity of 100 % and a specificity of 71 %, with a positive predictive value (PPV) of 54 % and a negative predictive value of 100 %; when considering high intensity, p16 IHC showed a sensitivity of 100 %, a specificity of 89 %, with a PPV of 75 % and NPV of 100 %. Since HPV positivity could represent a relevant prognostic and predictive value, the correct characterization offered by this approach appears to be of paramount importance.

Durable Complete Radiological Response to Nivolumab in Two Heavily Pretreated Western Elderly Patients With Metastatic Gastric Cancer: A Case Report.

Background: The prognosis of patients with advanced gastric cancer remains overall poor despite some recent innovations and the development of new therapeutic approaches. Current European guidelines do not recommend any specific treatment for patients with advanced gastric cancer refractory to two or more previous chemotherapy regimens, making this setting "orphan." Immunotherapy is quickly evolving also for this malignancy even if with controversial results and the correct patient selection is still debated, especially for Western patients. The phase III ONO-4538-12 "ATTRACTION-2" represents the current landmark trial for the development of immunotherapy for pretreated Asian patients and led to the approval of Nivolumab in some Asian countries, while only previous phase trials are available for Caucasians. Complete radiological response is anecdotic and has never been described both in the pivotal trial both in the others with Western patients enrolled. Case presentation: We report two cases of heavily pretreated Western elderly patients with metastatic gastric cancer who experienced durable complete radiological response to Nivolumab "off label" (more than 20 months to date) in a clinical practice context. Molecular analysis of potential predictive factors has been performed (PD-L1, EBV, MSI, and TMB) on primary tumor sample. Conclusions: Despite the lack of evidence for Western patients and the controversial outcome with the use of checkpoint inhibitors in previous settings, immunotherapy may dramatically change the prognosis and the natural history of pretreated Western metastatic gastric cancer, in a correctly selected population. Microsatellite instability and tumor mutational burden may be reliable predictive factors also for Caucasians. There is an urgent need for a change in clinical practice also for this "orphan" patients and more efforts are needed in order to clarify the role of predictive factors for a correct patient selection and better chances of survival for this awful malignancy.

Nivolumab in Heavily Pretreated Metastatic Gastric Cancer Patients: Real-Life Data from a Western Population.

PURPOSE: ATTRACTION-2 trial assessed the role of Nivolumab as a new standard treatment for Asian patients with pretreated metastatic gastric cancer (mGC). The aim of this analysis was to evaluate the safety and efficacy of Nivolumab in a real-life Western population, considering the lack of evidence to date. PATIENTS AND METHODS: Patients progressed after ≥2 chemotherapy regimens and able to receive Nivolumab (3 mg/kg q14) were eligible for the analysis. RESULTS: 16 patients received Nivolumab as third (81.3%) or fourth line (18.7%) from September 2017 to July 2019. The safety was in line with the literature and only one patient discontinued treatment due to persistent hematological toxicity. Overall response rate and disease control rate were 18.7% and 31.2%, respectively. Median duration of response was 5 months. With a median follow-up of 21 months, median OS was 6 months (7, 21 and 22 months in the responders) and median PFS 3 months. PD-L1 and microsatellite status were retrospectively collected in 12 patients. All the major responders were MSI, although no statistically significant difference in OS or PFS was observed according to molecular analysis. CONCLUSION: Nivolumab is feasible and effective in Western patients with mGC. Further investigation is urgently needed also in non-Asians.

Immunohistochemistry for Cancer Stem Cells Detection: Principles and Methods.

Cancer stem cells (CSCs) are rare immortal cells within a tumor that can self-renew and drive tumorigenesis. CSCs play a pivotal role in the tumor development, progression and relapse, as well as in the resistance of anticancer therapy. Different tools could help in the analysis of CSCs, especially Immunohistochemistry (IHC) represents a useful technique able to identify several specific CSC markers. The main aims of this chapter are the description of the explain immunohistochemical methods used in the characterization of CSCs. Furthermore, focus on the most common troubleshooting in CSCs IHC is provided, especially the pitfalls of the CSCs markers IHC on tissue microarrays.