Expression of ERG Protein and TMRPSS2-ERG Fusion in Prostatic Carcinoma in Egyptian Patients

Immunohistochemical Expression of Alpha-Methyl-Coa (AMACR) and ERG in Prostatic Adenocarcinoma and Prostatic Hyperplasia: A Comparative Study

OBJECTIVE

This observational comparative study aimed at investigating the diagnostic accuracy of ERG in differentiating benign and malignant prostatic lesions and comparing it to the diagnostic accuracy of AMACR. We also aimed at comparing AMACR and ERG expression to Gleason grade of the carcinoma cases.

METHODS

Seventy- two cases (22 prostatic hyperplasia and 50 prostatic carcinoma) were collected from the pathology department at Cairo university. The cases were immunostained by antibodies against AMACR and ERG. Immunohistochemical expressions of both markers were differentially examined in benign and malignant cases, compared to each other's, as well as, to the grade group of the malignant cases.

RESULTS

AMACR showed 62% sensitivity and 86.4% specificity for the diagnosis of PC, with a statistically significant differential expression in benign and malignant lesions (P=0.001). Its expression also correlated significantly with the age (p=0.007), Gleason grade (P=0.006) and perineural invasion (P=0.011). Although ERG showed 100% specificity to PC with no expression in hyperplasia cases, it showed only 22% sensitivity for PC cases. ERG expression also showed statistically significant correlation with the Gleason grade. No association between ERG and AMACR expression was detected in our study (P=0.151). Regarding the diagnostic accuracy, although ERG accuracy was much lower than that of AMACR, combining both markers yielded a higher diagnostic accuracy.

CONCLUSION

Although ERG proved no superior value than AMACR in diagnosing prostatic lesions, combining both markers may lead to higher diagnostic accuracy owing to higher ERG specificity for PC.

Investigation of Neural Microenvironment in Prostate Cancer in Context of Neural Density, Perineural Invasion, and Neuroendocrine Profile of Tumors

Background

Cancer stroma contains the neural compartment with specific components and action. Neural microenvironment processing includes among others axonogenesis, perineural invasion (PNI), neurosignaling, and tumor cell neural/neuroendocrine differentiation. Growing data suggest that tumor-neural crosstalk plays an important function in prostate cancer (PCa) biology. However, the mechanisms involved in PNI and axonogenesis, as well as their patho-clinical correlations in this tumor are unclear.

Methods

The present study was carried out on FFPE samples of 73 PCa and 15 benign prostate (BP) cases. Immunohistochemistry with neural markers PGP9.5, TH, and NFP was performed on constructed TMAs and selected tissue sections. The analyzed parameters of tumor innervation included small nerve density (ND) measured on pan-neural marker (PGP9.5) and TH s4tained slides, as well assessment of PNI presence and morphology. The qualitative and topographic aspects were studied. In addition, the expression of neuroendocrine marker chromogranin and NPY was assessed with dedicated indexes. The correlations of the above parameters with basic patho-clinical data such as patients’ age, tumor stage, grade, angioinvasion, and ERG status were examined.

Results

The study showed that innervation parameters differed between cancer and BP. The neural network in PCa revealed heterogeneity, and ND PGP9.5 in tumor was significantly lower than in its periphery. The density of sympathetic TH-positive fibers and its proportion to all fibers was lower in cancer than in the periphery and BP samples. Perineural invasion was confirmed in 76% of cases, usually multifocally, occurring more commonly in tumors with a higher grade. NPY expression in PCa cells was common with its intensity often rising towards PNI. ERG+ tumors showed higher ND, more frequent PNI, and a higher stage. Moreover, chromogranin-positive cells were more pronounced in PCa with higher NPY expression.

Conclusions

The analysis showed an irregular axonal network in prostate cancer with higher neural density (panneural and adrenergic) in the surroundings and the invasive front. ND and PNI interrelated with NPY expression, neuroendocrine differentiation, and ERG status. The above findings support new evidence for the presence of autocrine and paracrine interactions in prostate cancer neural microenvironment.

Comparative study of immunohistochemical expression of ERG and MAGI2 in prostatic carcinoma

Diagnosis of Prostatic adenocarcinoma (PAC) is still a problematic issue. The objective of this study was to evaluate the diagnostic and prognostic value of ERG immunohistochemical (IHC) expression compared to MAGI2.

MATERIALS AND METHODS

This study was conducted on 56 cases of PAC and 29 cases of nodular prostatic hyperplasia (NPH). IHC staining for ERG and MAGI2 was applied to archival formalin-fixed paraffin-embedded blocks. Semi-quantitative scoring was compared and correlated with clinicopathologic parameters and the Ki-67 index.

RESULTS

Revealed positive ERG in 51.8% of PAC while all NPH cases were negative. On the other hand, MAGI2 was detected in 91.1% of PAC versus 17.2% of NPH. Using ROC curve, the ERG showed 53.6% sensitivity, 100% specificity, 76.5% diagnostic accuracy (DA) and area under the ROC curve 0.768 in comparison to MAGI2 that showed (91.1%, 86.2%, 88.25% and 0.948 respectively). Analysis of the combined use of the two markers revealed 95% sensitivity, 100% specificity, and 94% DA when tested synchronously. Moreover, a statistically significant inverse relationship could be detected between ERG expression and the Gleason grading group (P = 0.01) and Ki-67 index (P < 0.001). In addition, high-grade prostatic intraepithelial neoplasia (HGPIN) adjacent to carcinoma; showed positive expressions in (1/11 cases, 9.11%) for ERG and (6/11 cases, 54%) for MAGI2.

CONCLUSION

This study recommends using both ERG and MAGI2 in a cocktail for better diagnostic validity of PAC. Only ERG expression could be a good prognostic indicator.

A Review of Cancer Genetics and Genomics Studies in Africa

Cancer is the second leading cause of death globally and is projected to overtake infectious disease as the leading cause of mortality in Africa within the next two decades. Cancer is a group of genomic diseases that presents with intra- and inter-population unique phenotypes, with Black populations having the burden of morbidity and mortality for most types. At large, the prevention and treatment of cancers have been propelled by the understanding of the genetic make-up of the disease of mostly non-African populations. By the same token, there is a wide knowledge gap in understanding the underlying genetic causes of, and genomic alterations associated with, cancer among black Africans. Accordingly, we performed a review of the literature to survey existing studies on cancer genetics/genomics and curated findings pertaining to publications across multiple cancer types conducted on African populations. We used PubMed MeSH terms to retrieve the relevant publications from 1990 to December 2019. The metadata of these publications were extracted using R text mining packages: RISmed and Pubmed.mineR. The data showed that only 0.329% of cancer publications globally were on Africa, and only 0.016% were on cancer genetics/genomics from Africa. Although the most prevalent cancers in Africa are cancers of the breast, cervix, uterus, and prostate, publications representing breast, colorectal, liver, and blood cancers were the most frequent in our review. The most frequently reported cancer genes were BRCA1, BRCA2, and TP53. Next, the genes reported in the reviewed publications’ abstracts were extracted and annotated into three gene ontology classes. Genes in the cellular component class were mostly associated with cell part and organelle part, while those in biological process and molecular function classes were mainly associated with cell process, biological regulation, and binding, and catalytic activity, respectively. Overall, this review highlights the paucity of research on cancer genomics on African populations, identified gaps, and discussed the need for concerted efforts to encourage more research on cancer genomics in Africa.

Poly(ADP-Ribose) Polymerase Inhibitors in Prostate Cancer: Molecular Mechanisms, and Preclinical and Clinical Data

Genomic instability is one of the hallmarks of cancer. The incidence of genetic alterations in homologous recombination repair genes increases during cancer progression, and 20% of prostate cancers (PCas) have defects in DNA repair genes. Several somatic and germline gene alterations drive prostate cancer tumorigenesis, and the most important of these are BRCA2, BRCA1, ATM and CHEK2. There is a group of BRCAness tumours that share phenotypic and genotypic properties with classical BRCA-mutated tumours. Poly(ADP-ribose) polymerase inhibitors (PARPis) show synthetic lethality in cancer cells with impaired homologous recombination genes, and patients with these alterations are candidates for PARPi therapy. Androgen deprivation therapy is the mainstay of PCa therapy. PARPis decrease androgen signalling by interaction with molecular mechanisms of the androgen nuclear complex. The PROFOUND phase III trial, comparing olaparib with enzalutamide/abiraterone therapy, revealed increased radiological progression-free survival (rPFS) and overall survival (OS) among patients with metastatic castration-resistant prostate cancer (mCRPC) with BRCA1, BRCA2 or ATM mutations. The clinical efficacy of PARPis has been confirmed in ovarian, breast, pancreatic and recently also in a subset of PCa. There is growing evidence that molecular tumour boards are the future of the oncological therapeutic approach in prostate cancer. In this review, we summarise the data concerning the molecular mechanisms and preclinical and clinical data of PARPis in PCa.