The utility of PSMA and PSA immunohistochemistry in the cytologic diagnosis of metastatic prostate carcinoma

Recent advances in the molecular targeted drugs for prostate cancer

CONTEXT

Prostate cancer (PCa) is the second largest male tumor in the world and one of the most common malignant tumors in the urinary system. In recent years, the incidence rate of PCa in China has been increasing year by year. Meanwhile, refractory hormone resistance and adverse drug reactions of advanced PCa cause serious harm to patients.

OBJECTIVE

The present study aims to systematically review the recent advances in molecularly targeted drugs for prostate cancer and to use the retrieval and analysis of the literature library to summarize the adverse effects of different drugs so as to maximize the treatment benefits of targeted therapies.

EVIDENCE ACQUISITION

We performed a systematic literature search of the Medline, EMBASE, PubMed, and Cochrane databases up to March 2022 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Medical Subject Heading (MeSH) terms and keywords such as (prostate cancer) AND (molecular target drugs) AND (side effect) were used. No language restrictions were set on the search process, and all these results were processed independently by two authors. Consensus was reached through discussion once met with any disagreements. The primary endpoint was differential features between different molecular targeted drugs. Secondary endpoints were side effects of different drugs on the body and corresponding prognostic values.

EVIDENCE SYNTHESIS

The Cochrane Collaboration risk of bias tool was used to assess the study quality in terms of sequence generation, allocation concealment, blinding, the completeness of outcome data, selective reporting and other biases. We retrieved 332 articles, of which 49 met the criteria for inclusion. Included studies show that prostatic tumor cells, tumor neovascularization and immune checkpoints are the main means for targeted therapy. Common drugs include 177 Lu-PSMA, Olaparib, Rucaparib, Bevacizumab, Pazopanib, Sorafenib, Cabozantinib, Aflibercept, Ipilimumab, Atezolizumab, Avelumab, Durvalumab. A series of publicly available data suitable for further analysis of side effects. An over-representation analysis of these datasets revealed reasonable dosage and usage is the key to controlling the side effects of targeted drugs. Important information such as the publication year, the first author, location and outcome observation of adverse effects was extracted from the original article. If the study data has some insufficient data, contacting the corresponding authors is necessary. All the studies included prospective nonrandomized and randomized research. Retrospective reviews were also screened according to the relevant to the purpose of this study. Meeting abstracts as well as letters to the editor and editorials were excluded.

STATISTICAL ANALYSIS

Data analysis was based on Cochrane's risk of bias tools to obtain the quality assessment. The included randomized studies used RoB2 and non-randomized ones corresponded to ROBINS-I. Standardized mean differences (SMD) were used to determine relative risk (RR) and side effects between groups. The eggers' test was used to check the publication bias from variable information in the included studies. All p < 0.05 were considered to be significant, and 95% was set as the confidence interval.

CONCLUSIONS

With the approval of a variety of targeted drugs, targeted therapy will be widely used in the treatment of advanced or metastatic prostate cancer. Despite the existence of adverse reactions related to targeted drug treatment, it is still meaningful to adjust the drug dosage or treatment cycle to reduce the occurrence of adverse reactions, improving the treatment benefits of patients.

Carcinoma of Unknown Primary Origin: Application of Immunohistochemistry With Emphasis to Different Cytokeratin 7 and 20 Staining Patterns

BACKGROUND

Although the primary origin of some carcinomas may be obscure to clinicians, its identification is crucial as it affects prognosis and treatment (especially novel targeted therapies). Immunohistochemistry (IHC) may be helpful in identifying the primary origin of carcinomas. This retrospective survey aimed to evaluate the frequency and accuracy of each IHC marker used to determine the origin of carcinomas.

METHODS

The review of pathology department archives revealed 307 cases of cancer of unknown primary origin (CUP) between 2015 and 2020, which were accessible in the department archives. Demographic information, site of biopsy, clinical and pathologic diagnoses, and IHC results of the patients were collected.

RESULTS

The patients included 157 (51.15%) men and 150 (48.85%) women. The age of the patients ranged from 14 to 92 years, including 106 (34.5%) expired cases. In 27% of cases, the primary origin of carcinoma remained unknown. The agreement between pathologic and clinical diagnoses was 59%. The most common pattern of cytokeratin (CK) expression in CUP was CK7+/CK20- (55.3%), followed by CK7-/CK20- (19%), CK7+/CK20+ (15%), and CK7-/CK20+ (10.7%), respectively.

CONCLUSION

The IHC analysis may improve the diagnosis of CUPs. However, the origin of some cases remains unknown despite an IHC analysis, thereby necessitating the use of more diagnostic procedures or gene expression studies for reaching a definitive diagnosis.

Cytokeratin 7 and cytokeratin 20 expression in cancer: A tissue microarray study on 15,424 cancers

Combined analysis of cytokeratin 7 (CK7) and cytokeratin 20 (CK20) is often used for assessing the origin of metastatic cancer. To evaluate the diagnostic utility of CK7 and CK20, tissue microarrays containing 15,424 samples from 120 different tumor types and subtypes and 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry. CK7 positivity was seen in 52% (8.7% weak, 5.9% moderate, 37% strong) and CK20 positivity in 23% (5.1% weak, 3.4% moderate, 15% strong) of interpretable tumors. Of 8390 positive tumors, 1181 (14%) showed positivity for CK7 and CK20, 5380 (64%) showed positivity for CK7 alone, and 1829 (22%) showed positivity for CK20 alone. CK20 predominated in gastrointestinal tract, urothelial and Merkel cell carcinomas. CK7 was usually negative in prostate cancer and colorectal cancer. Combined evaluation of CK7/CK20 revealed the best diagnostic utility in CK20 positive tumors, where CK7 negativity is often linked to colorectal origin while CK7 positivity argues for urothelial origin or mucinous ovarian cancer. Associations with unfavorable tumor features were found for cytokeratin 7 loss in breast cancer of no special type, urothelial and renal cell carcinomas, for CK7 overexpression in high-grade serous ovarian and gastric cancer, and for CK20 overexpression in urothelial carcinoma. CK20 loss was linked to MSI in gastric (p = 0.0291) and colorectal adenocarcinoma (p < 0.0001). These analyses provide comprehensive data on the frequency of CK7 and CK20 immunostaining - alone or in combination - in human cancers. These data facilitate interpretation of CK7/CK20 immunostaining in cancers.

A New Approach for Prostate Cancer Diagnosis by miRNA Profiling of Prostate-Derived Plasma Small Extracellular Vesicles

Vesicular miRNA has emerged as a promising marker for various types of cancer, including prostate cancer (PC). In the advanced stage of PC, the cancer-cell-derived small extracellular vesicles (SEVs) may constitute a significant portion of circulating vesicles and may mediate a detectable change in the plasma vesicular miRNA profile. However, SEVs secreted by small tumor in the prostate gland constitute a tiny fraction of circulating vesicles and cause undetectable miRNA pattern changes. Thus, the isolation and miRNA profiling of a specific prostate-derived fraction of SEVs can improve the diagnostic potency of the methods based on vesicular miRNA analysis. Prostate-specific membrane antigen (PSMA) was selected as a marker of prostate-derived SEVs. Super-paramagnetic beads (SPMBs) were functionalized by PSMA-binding DNA aptamer (PSMA-Apt) via a click reaction. The efficacy of SPMB-PSMA-Apt complex formation and PSMA(+)SEVs capture were assayed by flow cytometry. miRNA was isolated from the total population of SEVs and PSMA(+)SEVs of PC patients (n = 55) and healthy donors (n = 30). Four PC-related miRNAs (miR-145, miR-451a, miR-143, and miR-221) were assayed by RT-PCR. The click chemistry allowed fixing DNA aptamers onto the surface of SPMB with an efficacy of up to 89.9%. The developed method more effectively isolates PSMA(+)SEVs than relevant antibody-based technology. The analysis of PC-related miRNA in the fraction of PSMA(+)SEVs was more sensitive and revealed distinct diagnostic potency (AUC: miR-145, 0.76; miR-221, 0.7; miR-451a, 0.65; and miR-141, 0.64) than analysis of the total SEV population. Thus, isolation of prostate-specific SEVs followed by analysis of vesicular miRNA might be a promising PC diagnosis method.

Differential expression of NKX 3.1 and HOXB 13 in bone metastases originating from prostatic carcinoma among the Egyptian males

BACKGROUND

The skeleton represents one of the most common sites to be affected by metastatic tumors. About 65 % of all bone metastases come from the breast cancer in females, and from the prostatic carcinoma in males. A probable diagnostic pitfall may be encountered during the process of decalcification of the bone metastases specimens. This study aimed to evaluate the diagnostic utility of NKX3.1 and HOXB13 and compare them with the traditionally used PSA for the detection of prostatic origin of bone metastases.

MATERIAL AND METHODS

We analyzed 41 tissue specimens of bone metastases originating from prostatic carcinoma. Immunohistochemical staining of NKX3.1, HOXB13 and PSA was done with evaluation of their differential expression.

RESULTS

NKX3.1, HOXB 13 and PSA were expressed in (41/41), (39/41) and (25/41) respectively of the analyzed cases. On comparing NKX3.1 and HOXB13 positive staining, there was a statistically significant difference (P = 0.000). In addition, the frequency of positive NKX3.1 expression in decalcified bone biopsies of metastatic prostatic adenocarcinoma is statistically higher than that of PSA immunostaining (P = 0.000). We found a statistically significant difference between HOXB13 and PSA positive immunostaining (P = 0.01).

CONCLUSION

This study demonstrates that NKX3.1 and HOXB13 are more sensitive markers than PSA for the detection of prostate carcinoma metastatic to the bone following the decalcification process. We recommend use of NKX3.1 and HOXB13, rather than PSA, in the diagnosis of bone metastases originating from prostate cancer.

Deep Neural Network for Automatic Characterization of Lesions on 68Ga-PSMA PET/CT Images

The emerging PSMA-targeted radionuclide therapy provides an effective method for the treatment of advanced metastatic prostate cancer. To optimize the therapeutic effect and maximize the theranostic benefit, there is a need to identify and quantify target lesions prior to treatment. However, this is extremely challenging considering that a high number of lesions of heterogeneous size and uptake may distribute in a variety of anatomical context with different backgrounds. This study proposes an end-to-end deep neural network to characterize the prostate cancer lesions on PSMA imaging automatically. A ⁶⁸Ga-PSMA-11 PET/CT image dataset including 71 patients with metastatic prostate cancer was collected from three medical centres for training and evaluating the proposed network. For proof-of-concept, we focus on the detection of bone and lymph node lesions in the pelvic area suggestive for metastases of prostate cancer. The preliminary test on pelvic area confirms the potential of deep learning methods. Increasing the amount of training data may further enhance the performance of the proposed deep learning method.

Deep neural network for automatic characterization of lesions on 68Ga-PSMA-11 PET/CT

PURPOSE

This study proposes an automated prostate cancer (PC) lesion characterization method based on the deep neural network to determine tumor burden on ⁶⁸Ga-PSMA-11 PET/CT to potentially facilitate the optimization of PSMA-directed radionuclide therapy.

METHODS

We collected ⁶⁸Ga-PSMA-11 PET/CT images from 193 patients with metastatic PC at three medical centers. For proof-of-concept, we focused on the detection of pelvis bone and lymph node lesions. A deep neural network (triple-combining 2.5D U-Net) was developed for the automated characterization of these lesions. The proposed method simultaneously extracts features from axial, coronal, and sagittal planes, which mimics the workflow of physicians and reduces computational and memory requirements.

RESULTS

Among all the labeled lesions, the network achieved 99% precision, 99% recall, and an F1 score of 99% on bone lesion detection and 94%, precision 89% recall, and an F1 score of 92% on lymph node lesion detection. The segmentation accuracy is lower than the detection. The performance of the network was correlated with the amount of training data.

CONCLUSION

We developed a deep neural network to characterize automatically the PC lesions on ⁶⁸Ga-PSMA-11 PET/CT. The preliminary test within the pelvic area confirms the potential of deep learning methods. Increasing the amount of training data should further enhance the performance of the proposed method and may ultimately allow whole-body assessments.

Combining Diagnostic Imaging and Pathology for Improving Diagnosis and Prognosis of Cancer

In the era of personalized medicine, the management of oncological patients requires a translational and multidisciplinary approach. During early phases of cancer development, biochemical alterations of cell metabolism occur much before the formation of detectable tumour masses. Current molecular imaging techniques, targeted to the study of molecular kinetics, employ molecular tracers capable of detecting cancer lesions with both high sensitivity and specificity while also providing essential information for both prognosis and therapy. On the contrary, complementary and crucial information is provided by histopathological examination and ancillary techniques such as immunohistochemistry. Thus, the successful collaboration between diagnostic imaging and anatomic pathology can represent a fundamental step in the "tortuous" but decisive path towards personalized medicine.

Concise Review: Prostate Cancer Stem Cells: Current Understanding

Prostate cancer (PCa) is heterogeneous, harboring phenotypically diverse cancer cell types. PCa cell heterogeneity is caused by genomic instability that leads to the clonal competition and evolution of the cancer genome and by epigenetic mechanisms that result in subclonal cellular differentiation. The process of tumor cell differentiation is initiated from a population of prostate cancer stem cells (PCSCs) that possess many phenotypic and functional properties of normal stem cells. Since the initial reports on PCSCs in 2005, there has been much effort to elucidate their biological properties, including unique metabolic characteristics. In this Review, we discuss the current methods for PCSC enrichment and analysis, the hallmarks of PCSC metabolism, and the role of PCSCs in tumor progression. Stem Cells 2018;36:1457-1474.

Identifying cancer origin using circulating tumor cells

Circulating tumor cells (CTCs) have become an established clinical evaluation biomarker. CTC count provides a good correlation with the prognosis of cancer patients, but has only been used with known cancer patients, and has been unable to predict the origin of the CTCs. This study demonstrates the analysis of CTCs for the identification of their primary cancer source. Twelve mL blood samples were equally dispensed on 6 CMx chips, microfluidic chips coated with an anti-EpCAM-conjugated supported lipid bilayer, for CTC capture and isolation. Captured CTCs were eluted to an immunofluorescence (IF) staining panel consisting of 6 groups of antibodies: anti-panCK, anti-CK18, anti-CK7, anti-TTF-1, anti-CK20/anti-CDX2, and anti-PSA/anti-PSMA. Cancer cell lines of lung (H1975), colorectal (DLD-1, HCT-116), and prostate (PC3, DU145, LNCaP) were selected to establish the sensitivity and specificity for distinguishing CTCs from lung, colorectal, and prostate cancer. Spiking experiments performed in 2mL of culture medium or whole blood proved the CMx platform can enumerate cancer cells of lung, colorectal, and prostate. The IF panel was tested on blood samples from lung cancer patients (n = 3), colorectal cancer patients (n = 5), prostate cancer patients (n = 5), and healthy individuals (n = 12). Peripheral blood samples found panCK⁺ and CK18⁺ CTCs in lung, colorectal, and prostate cancers. CTCs expressing CK7⁺ or TTF-1⁺, (CK20/ CDX2)⁺, or (PSA/ PSMA)⁺ corresponded to lung, colorectal, or prostate cancer, respectively. In conclusion, we have designed an immunofluorescence staining panel to identify CTCs in peripheral blood to correctly identify cancer cell origin.

Prostate cancer metastasis to the distal phalanx of the left hallux: The first confirmed case and literature review

Prostate cancer is one of the most common carcinomas in Asia, as well as all over the world. The vast majority of prostate cancer patients present with bone metastases, which mainly involve the axial bones, with pain as the most common symptom. The present study reports the first case of prostate cancer metastasis to the hallux in a 73-year-old man who presented with pain and a swollen phalanx of the left hallux. This symptom developed gradually over a period of several months and could not be improved with the common treatments. Due to a pathological fracture, amputation of the left phalanx was performed. Notably, the immunohistochemical examinations of the surgical sample demonstrated the presence of a metastatic lesion from prostate cancer. The present study describes an unusual presentation involving phalangeal metastasis in a prostate cancer patient, and a systematic review of reported cases of rare metastatic events in prostate cancer is also discussed.

Heterogeneous PSMA expression on circulating tumor cells: a potential basis for stratification and monitoring of PSMA-directed therapies in prostate cancer

The prostate specific membrane antigen (PSMA) is the only clinically validated marker for therapeutic decisions in prostate cancer (PC). Characterization of circulating tumor cells (CTCs) obtained from the peripheral blood of PC patients might provide an alternative to tissue biopsies called "liquid biopsy". The aim of this study was to develop a reliable assay for the determination of PSMA on CTCs. PSMA expression was analyzed on tissue samples (cohort one, n = 75) and CTCs from metastatic PC patients (cohort two, n = 29). Specific signals for the expression of PSMA could be seen for different prostate cancer cell line cells (PC3, LaPC4, 22Rv1, and LNCaP) by Western blot, immunohistochemistry (IHC), immunocytochemistry (ICC), and FACS. PSMA expression was found to be significantly increased in patients with higher Gleason grade (p = 0.0011) and metastases in lymph nodes (p = 0.0000085) or bone (p = 0.0020) (cohort one). In cohort two, CTCs were detectable in 20 out of 29 samples (69 %, range from 1 - 1000 cells). Twelve out of 20 CTC-positive patients showed PSMA-positive CTCs (67 %, score 1+ to 3+). We found intra-patient heterogeneity regarding the PSMA status between CTCs and the corresponding primary tumors. The results of our study could help to address the question whether treatment decisions based on CTC PSMA profiling will lead to a measurable benefit in clinical outcome for prostate cancer patients in the near future.

Beyond the island: epigenetic biomarkers of colorectal and prostate cancer

Epigenetic dysregulation is a common feature across all cancer types. Epigenetic mechanisms, from DNA methylation to histone modifications, allow for a vast number of cellular phenotypes to be created from the same genetic material. Just as certain genetic changes play a key role in tumor initiation and progression, epigenetic changes may also set the course of tumor development and be required for malignant transformation. The most frequently studied epigenetic changes investigated thus far are global genomic DNA hypomethylation along with specific hypermethylation, predominantly at promoter CpG islands of tumor suppressor genes. In addition to DNA methylation changes at CpG islands, there is an abundance of other epigenetic alterations occurring within cancer cells including DNA methylation alterations outside of CpG islands, non-CpG methylation, changes in cytosine oxidative species (hydroxymethylcytosine, formylcytosine, carboxylcytosine) levels, and histone modifications. This chapter examines epigenetic alterations beyond the island, and summarizes recent findings in DNA-based epigenetic regulation of the two most commonly diagnosed cancers in the Western world: colorectal cancer and prostate cancer.