Review on Bladder Cancer Diagnosis

Abstract

Urothelial bladder carcinoma (UBC) is the foremost as often as possible analyzed cancer of the bladder in men around the world, and it positioned the 6th in terms of the number of cases analyzed. A total 30% of bladder tumors likely result from word-related introduction within the work environment to carcinogens. Approximately 70–75% of recently analyzed UBCs are low-grade or non-invasive. As of 2019, there is insufficient evidence to determine whether or not screening bladder cancer in patients without symptoms is feasible. The determination of UBC is made utilizing distinctive tests such as pee cytology and cystoscopy. Cytology tests are uncaring for low-grade cancer, whereas cystoscopy measures the measure of the sore. A biopsy will be done in the event that anomalous tissue is found amid cystoscopy. UBC can be recognized early by cytology, which has moo affectability for low-grade cancer, and by cystoscopy, which is intrusive and costly. Subsequently, numerous analysts have meticulously distinguished pee natural markers for non-invasive UC determination so that treatment victory can be expanded. Organic markers for early UBC discovery are summarized in this chapter, counting FDA-approved and exploratory markers, as well as a few of the unused innovations and developments that have the potential to help investigate endeavors in early UC detection.

1. Introduction

Urothelial bladder cancer (UBC) has a high incidence and prevalence due to its indolent nature, with 1, 15, 949 and 17, 20, 625 cases in 2020 according to the WHO [1]. Among men, the incidence of UBC is three times greater than among women (3:1), making it the fourth most frequent malignancy among men. The main risk factors are age, smoking, chlorination by-products in drinking water, and occupational exposures [2].

Urothelial cancer recurrence and progression have yielded a molecular route that scientists are now investigating for predictive and prognostic indicators [3]. In addition, the emergence of new noninvasive detection and surveillance techniques as well as possible treatment targets has been facilitated [4]. While multi-institutional randomized prospective studies are lacking, however, their prognostic and predictive indicators have not yet been validated for regular clinical usage. A total of 80% of these studies are in the process of being developed or are being worked on and will revolutionize how we diagnose, assess, and treat cancers [5].

Non-muscle invasive urothelial tumors are believed to arise by at least two molecular routes, either high-grade papillary tumors or CIS. Low-grade and high-grade tumors have different mutations, but invasion tumors have different mutations. Because cancers are more likely to arise from premalignant urothelial cells, it is surprising that multifocal and metachronal tumors have both common and novel mutations [6]. Poorly differentiated invasive urothelial carcinoma tumors have been shown to be related to the growing degree of genomic instability and are prone to have low copy number variations and reductions in heterozygosity. Many tumor suppressor genes and oncogenes are thought to be involved in the development of invasive urothelial carcinoma (IUC), though it is frequently difficult to determine whether these factors are required. As a result, it is not surprising that multifocal and metachronal tumors have both common and novel mutations. [7].

This review discusses an update on bladder cancer diagnosis, including the currently available role of bladder cancer tumor producers, part of urine markers in early identification of bladder cancer, the role of tissue markers for prognosis, and part of urine markers for patient investigation.

2. Bladder cancer tumor makers

In the absence of disease-specific signs, the urologic community has struggled to diagnose and monitor bladder cancer patients. As the standard for bladder cancer detection, cystoscopy is invasive and costly, which limits its usage. Fluorescence and narrow-band imaging are two new technologies, but they come with invasiveness and extra costs that outweigh the need for them as diagnostic tools in light of better, easier, and less expensive tests for treating bladder cancer patients [8].

It is also important to consider the cost of these tests, especially when similar information may be obtained using less expensive routine exams (cytology, cystoscopy) or additional permitted biomarkers. Costs, the difficulty of performance, the interpretation made confusion in a specific clinical setting, and the “psychological stress” experienced by both patient and physician when evaluating the reliability of a test outcome should all be considered when applying any marker for “routine” clinical use due to the critical nature of establishing some “added value” in the use of a particular test.

However, the research design, period of follow-up, and numbers required to give statistical power in the direction to confirm results may be limited in such early publications. These factors, together with the misapplication of findings to diverse clinical settings, might explain the typical inability to confirm promising but preliminary results [9].

Urine screening of people who had smoked for 40 years or more, using a combination of UroVysion, cytology, and urinary dipstick testing for hematuria, revealed cancer in 3.3% of these high-risk people [10]. Similarly, combining microsatellite analysis of exfoliated urine with UroVysion FISH (Fluorescence in situ hybridization) and conventional urine cytology allowed for the identification of approximately 93% of patients with recurrent bladder cancer [11]. The presence of microsatellite changes in urine has a strong link to invasive tumors in the bladder and has a high sensitivity for individuals with invasive cancer.

A surprise biomarker for bladder cancer is urinary hematuria, which develops in 85% of patients. The effectiveness of urine dipstick tests conducted at home and followed by medical evaluation might range from 90 to 95%. Muscle invasion was seen in only 10% of newly diagnosed bladder cancer patients who were tested for hematuria at home, compared to 60% of newly diagnosed bladder cancer patients who were not tested for hematuria [12]. Overall mortality was also lower than in unscreened individuals. Unfortunately, hematuria only has a 0.08% positive predictive value [13]. The stratification of hematuria-positive individuals into low and high-risk categories is therefore urgently required.

Patients with bladder cancer who are diagnosed with non-muscle invasive illness will need to be monitored for the rest of their lives. Current patient-monitoring methods typically include cystoscopic examinations every 3 months for the first 2 years of follow-up, twice a year for years three and four, and then yearly until disease recurrence is detected.

3. Role of urine markers in early detection of bladder cancer

The Food and Drug Administration (FDA) has authorized the custom of many commercially available urine-based diagnostics. However, none of these tests are commonly performed and are not included in the clinical guidelines for BC therapy published by the American Urological Association or the European Association of Urology [14].

These multi-urinary protein indicators were found to be beneficial in both high- and low-grade illnesses, as well as high- and low-stage diseases [15]. Midkine (MDK) and synuclein G or MDK, ZAG2 and CEACAM1 [16], angiogenin and clusterin [17] are measured by immunoassay and urine cytology improves the sensitivity and specificity in the diagnosis of non-muscle invasive bladder cancer (NMIBC) [16].

In the urine sediments of NMIBC patients, higher amounts of CK20 and Insulin- Like Growth Factor II (IGFII) were originate compared to controls [18]. Improved urine HAI-1 and Epcam levels, as measured by ELISA, are predictive indicators in individuals with high-risk NMIBC [19]. Urinary survivin, as measured by a chemiluminescence enzyme immunoassay, is associated with tumor stage, lymph node, and distant metastases, and may be used as a preliminary marker for BC diagnosis [20]. In NMIBC, snail overexpression is a distinct prognostic marker for tumor recurrence [21]. Glycan-affinity glycoproteomics nano-platforms identified specific glycoproteins in the urine of low- and high-grade NMIBC patients; high-grade MIBC patients had greater urinary CD44 levels [22].

Metabolic profiling of urine may potentially be beneficial for early detection of bladder cancer. The very sensitive super-performance liquid chromatography and mass spectrometry confirmed the presence of imidazole-acetic acid in BC [23]. A metabolite panel that may distinguish high- and low-grade breast cancer by using indolylacryloyl glycine, N2-galacturonyl-L-lysine, and aspartyl-glutamate is possible [24]. Furthermore, UPLC-MS was used to show that the phenylalanine, arginine, proline, and tryptophan metabolisms had been altered in NMBIC.

Immunoassay and FISH testing have expanded the diagnostic armamentarium to help us decide who needs further investigation. The “liquid biopsy” test has recently been employed to distinguish between NMIBC and MIBC in urine by detecting exosomes, cell-free proteins/peptides, circulating cell-free DNA, DNA methylation, and miRNA, [25]. Advanced “nano-sensors” able to detect RNA and proteins in urine are becoming closer to reality. It is not far off from being something we could easily implement [26]. A practical solution is needed for those findings, however, studies to confirm the efficacy of the recently identified urine biomarkers are not available [27, 28].

4. Role of tissue markers for prognosis

Currently, the biggest challenge is translating substantial proteomic and genomic data into clinical practice and validating the expression of these biomarkers in well-designed multicenter clinical trials.

The biggest class of membrane proteins for signal transduction on the cell surface, G-protein-coupled receptors (GPCRs), is used to detect ligands of unknown identity [29]. More than 800 GPCRs are found in the human genome, with most of them including seven homologous transmembrane domains [30, 31]. To stimulate the movement of particular ligands, GPCRs alter their conformations by interacting with the ligands. After this, the signaling network will activate, producing cellular responses including erythroid differentiation [32]. The following is an excerpt from a 2013 study that reports that there are over 100 orphan G-protein-coupled receptors (oGPCRs) for which their respective ligands are yet unknown [33]. A gene that encodes a G protein-coupled receptor, GPR137, is expressed mostly in the central nervous system, endocrine glands, thymus, and lungs [34]. Studies have revealed that GPCRs are vital to tumor development and metastasis.

Various activities performed by GPCRs, such as cell proliferation, survival, and motility, have been documented [35]. The GPCR48 receptor was found to be associated with the growth of prostate cancer cells, making it a viable target for treating the disease [36]. Smith and colleagues discovered that GPR30 was expressed preferentially in high-risk epithelial ovarian cancer, a finding that has been shown to correlate with worse survival rates in patients [37]. In addition, GPR161 expression was found in breast cancer and an earlier investigation revealed that the gene is a major regulator and a possible therapeutic target for three-fold negative breast cancer [38].

In the area of bladder tumor marker testing, urine proteins are assessed qualitatively or quantitatively, and antigens or chromosomal abnormalities are detected in urine cytology samples. These tumor marker assays had better sensitivity for detecting urothelial carcinoma when compared to urine cytology. The overall sample’s mean sensitivity and specificity were 64–80% and 71–95%, respectively, while the mean positive predictive value (PPV) and negative predictive value (NPV) for malignancy classification were 49–84% and 79–95%, respectively. During studies identifying proteins secreted into urine by bladder cancer cells, sensitivity was inadequate for Ta grade 1 bladder cancer. Since there are so many false-positive results with BTA TRAK, BTA stat, NMP22, and NMP22 Bladder Chek assays in patients with benign urological diseases like hematuria, urocystitis, renal calculi, or UTIs, as well as in patients with inserted catheters or intravesical manipulation in the last weeks, these tests are unreliable in these populations. If you are investigating a problem with BTA TRAK, BTA stat, NMP22, or NMP22 BladderChek, you must first eliminate other possible diagnoses, such as benign or malignant genitourinary illness, except for bladder cancer. The failure of urine tests to accurately diagnose bladder cancer or to be relied upon to guide treatment choice leads to a lack of appropriate sensitivity and specificity [39].

CD164, a member of the sialomucin family and previously known as endolyn or MGC-24v, was located on human chromosome 6q21 and is expressed and encoded by the CD164 gene [40, 41]. CD164 was originally discovered in primitive CD34+ hemopoietic progenitor cells and bone marrow stromal cells and is now known to have a role in adhesion, migration, and cell proliferation [42, 43, 44]. CD164, which was hypothesized to control hematopoiesis, was thought to have a role in promoting the adherence and migration of human CD34+ cells to bone marrow stroma [45]. A variety of malignancies in humans are known to have CD164 perform various functions. CD164, for example, has been documented for maintaining and progressing human malignancies, such as human glioma [46], lung cancer [47], ovarian cancer [48], and prostate cancer [49].

5. Role of urine markers for patient surveillance

Improved sequencing technology and a greater understanding of the molecular mechanisms of action for various treatments have both aided the study of BC tumor biology and how it affects MIBC and NMIBC. However, there are no clinically useful biomarkers available to accurately predict response to therapy in either the short- or long-term. An in-depth understanding of the clinicopathological parameters, such as tumor stage, grade, presence of CIS, tumor size, tumor multiplicity, and recurrence, is essential to properly predict treatment outcomes [50]. It was demonstrated that recurrence could be predicted with 85.5% accuracy using a cytokine panel after intravesical therapy (CyPRIT) (IL-2, IL-8, IL-6, IL-Ira, IL-18, IL-12), Il-12, tumour necrosis factor-, and tumour necrosis factor-, but its validity needed to be confirmed.

New discoveries related to the immunologic characteristics of bladder cancer (BC) have emerged as a promising prediction tool for intravesical BCG treatment and possibly immunotherapy in advanced cases [51]. While some studies found no link between programmed cell death protein ligand 1 (PDL-1) expression and the outcomes of NMIBC following BCG administration, others reported contradictory results and no convincing evidence [52]. It has been shown that an improved clinical result can be achieved by the assessment of BCG-specific T-cell immunity [53, 54]. In a study of BCG therapy, the T-cell and MDSC ratio in urine was associated with treatment failure [55].

A number of writers have attempted to find genetic alterations that might be associated with a response to the BCG vaccine. One example is the ARID1A mutation, which was found to increase the likelihood of BCG unresponsiveness [56]. Even while we now have non-invasive diagnostic tests and sensitive and specialized follow-up tests, our systems are still plagued by troublesome false positive findings. In addition to the presence of benign diseases including hematuria, cystitis, lithiasis, urinary tract infections, inflammation, and recurrent instrumentation, such as cystoscopy, false positive rates can develop due to many other reasons. Regardless, many kits have been on the market for quite some time. Even if most non-invasive techniques are better than standard cytology, this is not a hazard because of this superior performance. Due to the fact that none of these kits meet all requirements at all phases of BC detection, they have not yet been adopted in clinical practice. Patients and healthcare providers can benefit from each kit based on patient characteristics, context, and limits in detecting BC. Patients stratification is a crucial biological topic that is being addressed by the development of new biomarkers that can predict disease recurrence and response to medication. To be sure, cell-free (cfDNA) analysis in urine and/or serum will be able to overcome these barriers when liquid biopsies and precision oncology become more common [57].

Even for higher-grade bladder cancer, a number of molecular markers surpass urine cytology with regard to test sensitivity, as suggested by marker performance assessment. The cause of the decline in performance quality among pathologists is not known, however, it might be that it is caused by a reduction in urine cytology during the previous decade. The decreased specificity of molecular markers in the group studied seems insignificant because the priority is sensitivity when tracking individuals with high-grade malignancies. A further query is if at least some of the false-positive results may be an anticipatory positive finding, forecasting tumor recurrence [58, 59]. Studies indicating that molecular markers may improve the prognosis of bladder cancer patients with high-grade tumors are lacking, thus they are not widely accepted for therapeutic usage.

The vast array of mutations found in bladder cancer cases was revealed by a series of studies on next-generation sequencing, which found that more than 300 mutations were identified in each tumor, with 200 copy number changes and 20 rearrangements. Despite having a higher mutation rate, the only kind of cancer that has been found to have more mutations is lung cancer, and most of them are considered to be passenger mutations that have no effect [60].

A discussion on the clinical risk of recurrence and progression is, of course, ongoing, and several factors are in play, but largely because recurrence and advancement are both dictated by the presence of characteristics including size, multimodality, and time to recurrence. In addition, we must recognize that grading is primarily subjective and will, in the future, lead to increased reproducibility and improved association with a clinical result (either immunohistochemistry or molecular testing [61]. Hyperplasia was made obsolete when the phrase urothelial proliferation with undetermined malignant potential was established [62, 63]. The urothelium is thicker with few or no cytological abnormalities and a lack of genuine papillary fronds, however, undulations are sometimes present. These features may be observed in this context without any known history. When previous cancer or papillary lesions are present, those with carcinoma tend to have them. Lateral expansion of papillary carcinoma is expected, with high rates of chromosome 9 deletions and lower but still substantial rates of FGFR3 abnormalities. A flat lesion with cytologic and architectural abnormalities that are thought to be preneoplastic but do not meet the requirements for urothelial CIS is known as urothelial dysplasia. Because it seldom arises de novo, it is not well investigated. Of greater significance, this is the most difficult group to characterize morphologically because of a substantial inter-observer variability and a total lack of major clinical trials demonstrating its association with the later development of CIS.

6. Conclusion

The wide range of bladder cancer indicators enhances the prospect of making a breakthrough in the detection of cancer by using chosen markers, either in combination or individually. Hence panel testing is useful for increasing the detection of bladder cancer as well as for enhancing the accuracy of that detection. It is unquestionably crucial to test the clinical usefulness of this kind of panel before it can be used in standard medical treatment. The stability of these tumor marker analytes should also be better characterized in order to avoid false negative findings. A greater understanding of circumstances that result in false positives for urine-based indicators for cancer diagnosis might make them more effective.