Evaluation of the Expression EGFR, HER2/NEU and the End Effector ERK of the RAS/RAF/MAP Kinase Pathway in Prostatic Adenocarcinoma for a Possible Role as New Target Therapy.

The alterations of EGFR and HER2/neu as growth factor receptors and the cytoplasmic signal transduction proteins of RAS/RAF/MAP kinases including its end effector molecule (ERK) are important in the carcinogenesis of many tumors. The activation of these protooncogenes in prostate cancer is still under investigation. The aim of this work was to study EGFR, HER2- neu, inactive (non-phosphorylated) and active (phosphorylated) ERK expression in prostatic adenocarcinomas in correlation to the clinical and pathological parameters. METHODS: Immunohistochemistry- using tissue microarrays- for EGFR, HER2/neu, non-phosphorylated, and phosphor-ERK, was performed on tissues from 166 patients- with primary prostatic adenocarcinoma with no prior treatment-. The results of different markers expression were correlated with the clinical and pathological parameters and were analyzed statistically. RESULTS: The prostatic tissue showed EGFR, HER2 neu, phosphorylated and non-phosphorylated ERK expression in 8.4%, 1.4%, 78.2%, and 83.4% respectively whether low (patchy) or high expression (diffuse).  There were no significant correlations found between patient characteristics and expression of the tested markers. The negative immune reactivity for non-phosphorylated ERK and EGFR- was significantly correlated with high tumor stage (p values 0.03 and 0.01, respectively). CONCLUSION: EGFR and HER2/neu may play a limited role in prostatic adenocarcinoma as they showed positive expression in a limited number of the examined tissues specifically HER2neu. The expression of non-phosphorylated ERK (mostly weak to moderate) and phosphorylated ERK (mostly moderate to strong)- was appreciated in most cases. Thus, we suggest that anti-EGFR drugs may have a limited role in the treatment of castrate-resistant prostate cancer, but anti-MEK/ERK drugs may have more promising role as a target therapy. It is recommended to perform further molecular testing to elucidate the exact mechanism and significance of these markers.

Clinicopathological Study of Breast Carcinoma Patients with Equivocal HER2 Immunohistochemical Status: Five-Year Experience from a Tertiary Care Center.

Background and objectives: Assessment of HER2 gene status has central role in the management of breast cancer patients. For determining HER2 status, immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) are the most commonly used tests. Immunohistochemistry scores of 3+ and 1+ were considered as HER2 positive and negative, respectively. On the other hand, HER2 equivocal cases need further confirmation by FISH test assessment. This study aimed to identify the clinicopathological characteristics of patients with HER2 equivocal tumors served by Sultan Qaboos University Hospital (SQUH) in Muscat, Oman, with emphasis on treatment plans and disease outcome. Methods: This was a retrospective cross-sectional study, which involved all breast cancer female patients who were referred to SQUH from 2016 to 2020. It included a total of 108 patients who were diagnosed with HER2 (2+) breast cancer. Patients' data were analyzed in relation to the subsequent FISH status. Results: During the study period, data from 108 females with HER2 2+ were collected; among them, 22 (20%) were FISH positive, 64 (59%) FISH negative, 17 (16%) FISH borderline and five (5%) with no results. Regarding patients' characteristics, 91.2% of all subjects had invasive ductal carcinoma, 93.2% expressed estrogen receptors and 77.6% progesterone receptor. Age, postmenopausal histopathology, tumor grade, TNM staging, ER, PR, Ki67, LVSI, NLR, treatment and follow-up did not show significant association with different FISH results. Conclusions: The majority of HER2 equivocal breast cancer cases were FISH negative. In trastuzumab chemotherapy, an association between different FISH results was expected.

Human macrophages and monocyte-derived dendritic cells stimulate the proliferation of endothelial cells through midkine production.

The cytokine midkine (MK) is a growth factor that is involved in different physiological processes including tissue repair, inflammation, the development of different types of cancer and the proliferation of endothelial cells. The production of MK by primary human macrophages and monocyte-derived dendritic cells (MDDCs) was never described. We investigated whether MK is produced by primary human monocytes, macrophages and MDDCs and the capacity of macrophages and MDDCs to modulate the proliferation of endothelial cells through MK production. The TLR stimulation of human monocytes, macrophages and MDDCs induced an average of ≈200-fold increase in MK mRNA and the production of an average of 78.2, 62, 179 pg/ml MK by monocytes, macrophages and MDDCs respectively (p < 0.05). MK production was supported by its detection in CD11c+ cells, CLEC4C+ cells and CD68+ cells in biopsies of human tonsils showing reactive lymphoid follicular hyperplasia. JSH-23, which selectively inhibits NF-κB activity, decreased the TLR-induced production of MK in PMBCs, macrophages and MDDCs compared to the control (p < 0.05). The inhibition of MK production by macrophages and MDDCs using anti-MK siRNA decreased the capacity of their supernatants to stimulate the proliferation of endothelial cells (p = 0.01 and 0.04 respectively). This is the first study demonstrating that the cytokine MK is produced by primary human macrophages and MDDCs upon TLR triggering, and that these cells can stimulate endothelial cell proliferation through MK production. Our results also suggest that NF-κB plays a potential role in the production of MK in macrophages and MDDCs upon TLR stimulation. The production of MK by macrophages and MDDCs and the fact that these cells can enhance the proliferation of endothelial cells by producing MK are novel immunological phenomena that have potentially important therapeutic implications.

Programmed Death-ligand 1 (PD-L1) Expression in Bladder Cancer and its Correlation with Tumor Grade, Stage, and Outcome.

Objectives: To evaluate the expression of programmed death-ligand 1 (PD-L1) in bladder cancer cases in Oman using immunohistochemistry, and to determine whether the level of PD-L1 expression is associated with tumor grade, stage, or outcome. An additional objective was to identify the clinicopathological features of bladder cancer among Omanis. Methods: This was a retrospective cohort study of patients where we subjected archived tissue samples to prospective analysis. All patients diagnosed and treated for bladder cancer in Sultan Qaboos University Hospital from January 2006 to December 2017 and followed up for at least one year were included. Clinical and demographical information of the patients was obtained from their medical records. PD-L1 testing using immunohistochemistry was performed on formalin-fixed paraffin-embedded tissue blocks. Scoring of PD-L1 expression by tumor cells was conducted independently by two pathologists. Positivity was defined using two different cut-off values (≥ 5% and ≥ 25%) of tumor cells showing membrane or cytoplasmic staining. The outcome was divided into two categories either no recurrence at the last follow-up, or recurrence/disease progression/death. Results: There were 68 cases of bladder cancer; 72.1% were male; the age range was 35-89 years (mean = 65.3 and median = 66). The largest number of patients were diagnosed with stage II cancer (38.8%) followed by stage I cancer (32.8%). Hematuria was the most common presentation (58.7%). High-grade tumors were seen in 83.8% (57/68) of patients. Invasive urothelial carcinoma appeared in 79.4% (54/68). PD-L1 tests were performed on 63 cases where tissue blocks were available. PD-L1 was positive in 44.4% of cases using a cut-off value of 5%; however, it dropped to 30.2% at a cut-off value of 25%. At the cut-off value of 5%, PD-L1 was significantly associated with tumor grade (p = 0.033), but the significance was lost when the cut-off value of 25% was applied (p = 0.250). No significant association was found between PD-L1 expression and outcome using both cut-off values and stage at diagnosis (p = 0.798 and p = 0.102, respectively). Conclusions: This study showed that at a cut-off value of ≥ 5%, 44.4% of cases of bladder cancer were PD-L1 positive. There was a significant association between PD-L1 expression in bladder cancer and tumor grade. No statistically significant association was found between tumor stage and outcome. The results indicated the potential benefit of anti-PD-L1 immunotherapy for patients with high tumor grades.

Diagnostic Usefulness of p16 Immunohistochemistry for some Epithelial Lesions in the Pathology Service of Sultan Qaboos University Hospital.

Objectives:This study is aiming to assess the diagnostic value of p16 immunohistochemistry (IHC) for a variety of epithelial lesions in the service provided by the Department of Pathology at Sultan Qaboos University Hospital (SQUH), Sultanate of Oman. This study would enhance pathologists' ability to diagnose and differentiate between different types of epithelial lesions reliably. Methods:This study is a retrospective observational cross-sectional study. A total of 117 immunohistochemical tests for p16 were collected from the pathology lab at SQUH from January 2010 to December 2020. Data was analyzed using SPSS software. For numerical data, mean and percentages were used. For measuring the association between different pathological and clinical findings, the categorized variables were analyzed using the chi-square test. Results:Immunohistochemistry of p16 was mainly used to diagnose uterine cervical, ovarian, oropharyngeal and anal epithelial lesions. Predominately, it was applied on cervical intraepithelial neoplasia grades 1, 2 and 3 (CIN I, II, III), squamous metaplasia, chronic cervicitis, anal intraepithelial neoplasia as well as different types of squamous cell carcinoma, adenocarcinoma, and serous carcinoma. Conclusion:The results of the present study revealed the wide application of p16 IHC as a marker to reach the final histopathological diagnosis of epithelial lesions in the pathology lab at SQUH. The marker can be used effectively to differentiate between different types of lesions showing similar appearance on hematoxylin and eosin stain.

Immunohistological insight into the correlation between neuropilin-1 and epithelial-mesenchymal transition markers in epithelial ovarian cancer.

The mechanism by which neuropilin-1 (NRP-1) induces malignancy in Epithelial Ovarian Cancer (EOC) is still unknown. This study is the first to demonstrate the relationship between NRP-1 expression and EMT markers vimentin, N-cadherin, E-cadherin and Slug. We used tissue microarrays containing the three main subtypes of EOC tumors: serous, mucinous cystadenocarcinoma and endometrioid adenocarcinoma and representative cases retrieved from our pathology archives. Immunohistochemistry was performed to detect the expression levels and location of NRP-1 and the aforementioned EMT proteins. NRP-1 was mainly expressed on cancer cells but not in normal ovarian surface epithelium (OSE). The Immunoreactive Scoring (IRS) values revealed that the expression of NRP-1, Slug and E-cadherin in the malignant subtypes of ovarian tissues was significantly higher (5.18 ± 0.64, 4.84 ± 0.7, 4.98 ± 0.68, respectively) than their expression in the normal and benign tissues (1.04 ± 0.29, 0.84 ± 0.68, 1.71 ± 0.66, respectively), with no significant differences among the studied subtypes. Vimentin was expressed in the cancer cell component of 43% of tumors and it was exclusively localized in the stroma of all mucinous tumors. The Spearman's rho value indicated that NRP-1 is positively related to the EMT markers E-cadherin and Slug. This notion might indicate that NRP-1 is a partner in the EMT process in EOC tumors.