Quantifying the ki-67 heterogeneity profile in prostate cancer

A Study of Ki-67 Immunostaining in Prostate Carcinomas and Its Correlation with Gleason's Score and Prognosis: An Experience at a Tertiary Centre in the Himalayan Foothills

Prostate cancer is a significant cause of cancer-related mortality among men worldwide, necessitating the exploration of prognostic biomarkers to aid in accurate risk assessment and treatment decision-making. This cross-sectional study aimed to comprehensively evaluate the role of Ki-67 as a prognostic marker in prostate cancer by examining its association with clinicopathological parameters. A total of 102 archived cases of prostate core biopsy specimens, histopathologically reported as prostate carcinoma, were included in this study. Histopathological grading was conducted using Gleason's scoring and grading system based on morphology. The statistical software "R" was utilized for data analysis. Kruskal-Wallis test and Fisher's exact test were employed to analyze the association between Ki-67 expression and clinicopathological parameters. The study revealed significant correlations between Ki-67 expression and various clinicopathological parameters in prostate cancer cases. High Ki-67 expression levels were associated with higher Gleason scores, increased incidence of perineural invasion, advanced T stages, lymph node metastasis, presence of distant metastasis, and higher prognostic stage groups. The findings of this cross-sectional study support the potential of Ki-67 as a prognostic marker in prostate cancer. The significant associations observed between Ki-67 expression and clinicopathological parameters indicate its usefulness in risk stratification and treatment decision-making. The incorporation of histopathological grading, including Gleason scoring, and analysis of perineural invasion strengthens the validity of the study. Ki-67, in combination with morphological assessments, provides valuable prognostic information for prostate cancer patients.

Multiparametric MRI radiomics in prostate cancer for predicting Ki-67 expression and Gleason score: a multicenter retrospective study

PURPOSE

Prostate cancer (PCa) with high Ki-67 expression and high Gleason Scores (GS) tends to have aggressive clinicopathological characteristics and a dismal prognosis. In order to predict the Ki-67 expression status and the GS in PCa, we sought to construct and verify MRI-based radiomics signatures.

METHODS AND MATERIALS

We collected T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and apparent diffusion coefficient (ADC) images from 170 PCa patients at three institutions and extracted 321 original radiomic features from each image modality. We used support vector machine (SVM) and least absolute shrinkage and selection operator (LASSO) logistic regression to select the most informative radiomic features and built predictive models using up sampling and feature selection techniques. Using receiver operating characteristic (ROC) analysis, the discriminating power of this feature was determined. Subsequent decision curve analysis (DCA) assessed the clinical utility of the radiomic features. The Kaplan-Meier (KM) test revealed that the radiomics-predicted Ki-67 expression status and GS were prognostic factors for PCa survival.

RESULT

The hypothesized radiomics signature, which included 15 and 9 selected radiomics features, respectively, was significantly correlated with pathological Ki-67 and GS outcomes in both the training and validation datasets. Areas under the curve (AUC) for the developed model were 0.813 (95% CI 0.681,0.930) and 0.793 (95% CI 0.621, 0.929) for the training and validation datasets, respectively, demonstrating discrimination and calibration performance. The model's clinical usefulness was verified using DCA. In both the training and validation sets, high Ki-67 expression and high GS predicted by radiomics using SVM models were substantially linked with poor overall survival (OS).

CONCLUSIONS

Both Ki-67 expression status and high GS correlate with PCa patient survival outcomes; therefore, the ability of the SVM classifier-based model to estimate Ki-67 expression status and the Lasso classifier-based model to assess high GS may enhance clinical decision-making.

Tissue- and Liquid-Based Biomarkers in Prostate Cancer Precision Medicine

Worldwide, prostate cancer (PC) is the second-most-frequently diagnosed male cancer and the fifth-most-common cause of all cancer-related deaths. Suspicion of PC in a patient is largely based upon clinical signs and the use of prostate-specific antigen (PSA) levels. Although PSA levels have been criticised for a lack of specificity, leading to PC over-diagnosis, it is still the most commonly used biomarker in PC management. Unfortunately, PC is extremely heterogeneous, and it can be difficult to stratify patients whose tumours are unlikely to progress from those that are aggressive and require treatment intensification. Although PC-specific biomarker research has previously focused on disease diagnosis, there is an unmet clinical need for novel prognostic, predictive and treatment response biomarkers that can be used to provide a precision medicine approach to PC management. In particular, the identification of biomarkers at the time of screening/diagnosis that can provide an indication of disease aggressiveness is perhaps the greatest current unmet clinical need in PC management. Largely through advances in genomic and proteomic techniques, exciting pre-clinical and clinical research is continuing to identify potential tissue, blood and urine-based PC-specific biomarkers that may in the future supplement or replace current standard practices. In this review, we describe how PC-specific biomarker research is progressing, including the evolution of PSA-based tests and those novel assays that have gained clinical approval. We also describe alternative diagnostic biomarkers to PSA, in addition to biomarkers that can predict PC aggressiveness and biomarkers that can predict response to certain therapies. We believe that novel biomarker research has the potential to make significant improvements to the clinical management of this disease in the near future.

The role of androgen receptors in vascular and cell proliferation of the prostate adenocarcinomas

Prostate adenocarcinoma (PA) is by incidence and prognosis a unique model for investigating the biomolecular mechanisms involved in tumor progression. In this study, we analyzed the immunoexpression of androgen receptor (AR), cluster of differentiation 105 (CD105) and Ki67 for 61 cases of PA, in relation to the main clinicopathological parameters of the lesions. The AR scores, CD105 microvessel density (MVD) and Ki67 proliferation index (PI) were significantly higher in patients with serum prostate-specific antigen (PSA) above 20 ng/mL, in ductal, colloid and sarcomatoid types of PA, in growth patterns 4–5 or mixed, respectively in the case of high-grade advanced stage tumors, with perineural and vascular invasion, as well as in groups with a reserved prognosis. The results obtained, reflected in the positive linear correlation of AR, CD105 and Ki67 expression, indicate synchronous endocrine, angiogenic and proliferative mechanisms involved in tumor progression, which can be used to optimize the targeted tumor therapy.

Apoptotic and predictive factors by Bax, Caspases 3/9, Bcl-2, p53 and Ki-67 in prostate cancer after 12 Gy single-dose

Radio-induced apoptosis is mediated by the activation of tumor protein p53, Bax and caspases. The purpose of this study was to investigate the early activation of this pathway in men receiving in vivo irradiation immediately before radical prostatectomy for locally advanced prostate cancer. We also investigated cell proliferation index (Ki-67), proto-oncogene (p53) and anti-apoptotic protein (Bcl-2) levels as potential predictive factors. We selected a homogeneous sample of 20 patients with locally advanced prostate cancer and candidate to radical prostatectomy. To assess the apoptotic pathways, Bax, is studied through immunofluorescence assay, before and after 12 Gy single dose intraoperative radiotherapy (IORT) to the prostate, on bioptic samples and on surgical specimens. Moreover, before and after IORT, Bcl-2, p53, and Ki-67 were also detected through immunohistochemistry. A count of positive Bax spots for immunofluorescence was performed on tumor cells, prostatic intraepithelial neoplasia (PIN), and healthy tissue areas before and after IORT. We also analyzed Caspases 3 and 9 expressions after IORT. Before IORT, Bcl-2 mean value in neoplastic cells was 2.23% ± 1.95, mean Ki-67 in neoplastic area was 4.5% ± 3.8, and p53 was 22.5% ± 6.8. After IORT, Bcl-2 mean value in neoplastic cells was 8.85 ± 8.92%, Ki-67 in neoplastic area was 7.8 ± 6.09%, and p53 was 24.9 ± 26.4%. After the irradiation, healthy areas expressed significantly lower levels of Bax (2.81 ± 1.69%) with respect to neoplastic cells (p < 0.0001), while in PIN areas, Bax positive cells were significantly more present than in neoplastic areas (p = 0.0001). At statistical analysis, it was observed that cancer cells with Ki-67 ≥ 8% had a trend toward greater expression of Bax (p = 0.0641). We observed an increase of Bcl-2 expression after IORT in neoplastic areas (p = 0.0041). Biopsy specimens with p53 ≥ 18% and Ki-67 ≥ 8% had worse post-operative staging with extracapsular invasion (p = 0.04 for both parameters) and nodal positivity (p = 0.04 for p53 and p = 0.0001 at pathology for ki-67). No correlation between IORT and Caspases activation was noted. In conclusion, after 12 Gy IORT, Bax was overexpressed in tumor and PIN cells. Pre-operative Ki-67 and p53 definition could be used in future studies to predict patients with worse pathological stage, while Bcl-2 activation after IORT might be a predictive factor for loco-regional failure.

Pharmacodynamics effects of CDK4/6 inhibitor LEE011 (ribociclib) in high-risk, localised prostate cancer: a study protocol for a randomised controlled phase II trial (LEEP study: LEE011 in high-risk, localised Prostate cancer)

INTRODUCTION

Despite the development of new therapies for advanced prostate cancer, it remains the most common cause of cancer and the second leading cause of cancer death in men. It is critical to develop novel agents for the treatment of prostate cancer, particularly those that target aspects of androgen receptor (AR) signalling or prostate biology other than inhibition of androgen synthesis or AR binding. Neoadjuvant pharmacodynamic studies allow for a rational approach to the decisions regarding which targeted therapies should progress to phase II/III trials. CDK4/6 inhibitors have evidence of efficacy in breast cancer, and have been shown to have activity in preclinical models of hormone sensitive and castrate resistant prostate cancer. The LEEP trial aims to assess the pharmacodynamic effects of LEE011 (ribociclib), an orally bioavailable and highly selective CDK4/6 inhibitor, in men undergoing radical prostatectomy for high-risk, localised prostate cancer.

METHODS AND ANALYSIS

The multicentre randomised, controlled 4:1 two-arm, phase II, open label pharmacodynamic study will recruit 47 men with high risk, localised prostate cancer who are planned to undergo radical prostatectomy. Participants who are randomised to receive the study treatment will be treated with LEE011 400 mg daily for 21 days for one cycle. The primary endpoint is the frequency of a 50% reduction in Ki-67 proliferation index from the pretreatment prostate biopsy compared to that present in prostate cancer tissue from radical prostatectomy. Secondary and tertiary endpoints include pharmacodynamic assessment of CDK4/6 cell cycle progression via E2F levels, apoptotic cell death by cleaved caspase-3, changes in serum and tumour levels of Prostate Specific Antigen (PSA), pathological regression, safety via incidence of adverse events and exploratory biomarker analysis.

ETHICS AND DISSEMINATION

The protocol was approved by a central ethics review committee (St Vincent's Hospital HREC) for all participating sites (HREC/17/SVH/294). Results will be disseminated in peer-reviewed journals and at scientific conferences.

DRUG SUPPLY

Novartis.

PROTOCOL VERSION

2.0, 30 May 2019 TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry (ACTRN12618000354280).

Comparison of cell cycle progression score with two immunohistochemical markers (PTEN and Ki-67) for predicting outcome in prostate cancer after radical prostatectomy

PURPOSE

Previous studies of the cell cycle progression (CCP) score in surgical specimens of prostate cancer (PCa) in patients treated by radical prostatectomy (RP) demonstrated significant association with time to biochemical recurrence (BCR). In this study, we compared the ability of the CCP score and the expression of PTEN or Ki-67 to predict BCR in a cohort of patients treated by RP. Finally, we constructed the best predictive model for BCR, incorporating biomarkers and relevant clinical variables.

MATERIALS AND METHODS

The study population consisted of 652 PCa patients enrolled in a retrospective cohort and who had RP surgery in French urological centers from 2000 to 2007.

RESULTS

Among the 652 patients with CCP scores and complete clinical data, BCR events occurred in 41%, and the median time from surgery to the last follow-up among BCR-free patients was 72 months. In univariate Cox analysis, the continuous CCP score and positive Ki-67 predicted recurrence with a HR of 1.44 (95% CI 1.17-1.75; p = 5.3 × 10^-4) and 1.89 (95% CI 1.38-2.57; p = 1.6 × 10^-4), respectively. In contrast, PTEN expression was not associated with BCR risk. Of the three biomarkers, only the CCP score remained significantly associated in a multivariable Cox model (p = 0.026). The best model incorporated CAPRA-S and CCP scores as predictors, with HRs of 1.32 and 1.24, respectively.

CONCLUSION

The CCP score was superior to the two IHC markers (PTEN and Ki-67) for predicting outcome in PCa after RP.

Ki-67 expression predicts biochemical recurrence after radical prostatectomy in the setting of positive surgical margins

Background

Positive surgical margin (PSM) is a predictor of biochemical recurrence (BCR) following radical prostatectomy (RP). Attempts to stratify PSM based on linear length, Gleason score, location and number have failed to add to predictive models using margin status alone. We evaluated the prognostic significance of Ki-67 expression in this setting.

Methods

Immunohistochemical staining for Ki-67 was done on prostatectomy specimens from 117 patients who had a PSM. Ki67 expression was measured at the margin and in the index lesion. Patients were dichotomized based on Ki-67 expression into three groups. Group 1 with no Ki-67 expression, Group 2 with Ki-67 ≤ 2%, and Group 3 with Ki-67 ≥ 3%.

To eliminate the impact of the adjuvant treatment (AT) on the outcome, data were analyzed by the Cox proportional hazards in which AT was Considered as a time-dependent covariate.

Results

The discordance rate of Ki-67 expression between matched index lesion and margin specimens was 44/117 (37.6%). There was a trend for higher risk of BCR (HR:2.06, (0.97–4.43), P = 0.06) in patients expressing high Ki67 at the surgical margin although this was not statistically significant. However High Ki-67 expression in the index lesion was an independent predictive factor for BCR in this subset of patients. (HR:4, (1.64–9.80), P = 0.002).

Conclusion

High Ki67 expression in the index prostate cancer lesion is an independent predictor of BCR in patients with positive surgical margin following radical prostatectomy. Our findings need to be validated in a larger cohort.

Apparent diffusion coefficients in prostate cancer: correlation with molecular markers Ki-67, HIF-1α and VEGF

Prostate cancer (PCa) is the second most common cancer in men. The Gleason score (GS) and biomarkers play important roles in the diagnosis and treatment of patients with PCa. The purpose of this study was to investigate the relationship between the apparent diffusion coefficient (ADC) and the molecular markers Ki-67, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in PCa. Thirty-nine patients with 39 lesions, who had been diagnosed with PCa, were enrolled in this study. All patients underwent diffusion-weighted magnetic resonance imaging (DW-MRI) (b = 800 s/mm² ). The expression of Ki-67, HIF-1α and VEGF was assessed by immunohistochemistry. Statistical analysis was applied to analyze the association between ADC and prostate-specific antigen (PSA), GS and the expression of Ki-67, HIF-1α and VEGF. The group differences in ADC among different grades of Ki-67, HIF-1α and VEGF were also analyzed. The mean ± standard deviation of ADC was (0.76 ± 0.27) × 10^-3  mm² /s. ADC correlated negatively with PSA and GS (p < 0.05). The Ki-67 staining index (SI), HIF-1α expression and VEGF expression in PCa were correlated inversely with ADC, controlling for age (r = -0.332, p < 0.05; r = -0.662, p < 0.0005; and r = -0.714, p < 0.0005, respectively). ADC showed a significant difference among different grades of Ki-67 (F = 9.164, p = 0.005), HIF-1α (F = 40.333, p < 0.0005) and VEGF (F = 22.048, p < 0.0005). In conclusion, ADC was correlated with PSA, GS, and Ki-67, HIF-1α and VEGF expression in patients with PCa. ADC may be used to evaluate tumor proliferation, hypoxia and angiogenesis in PCa.

Evaluation of the proliferation marker Ki-67 in a large prostatectomy cohort

The tumor proliferation index marker Ki-67 is strongly associated with tumor cell proliferation, growth and progression, and is widely used in routine clinicopathological investigation. Prostate cancer is a complex multifaceted and biologically heterogeneous disease, and overtreatment of localized, low volume indolent tumors, is evident. Here, we aimed to assess Ki-67 expression and related outcomes of 535 patients treated with radical prostatectomy. The percentage of tumor epithelial cells expressing Ki-67 was determined by immunohistochemical assay, both digital image analysis and visual scoring by light microscope were used for quantification. The association of Ki-67 and prostate cancer was evaluated, as well as its prognostic value. There was a positive correlation between high expression of Ki-67 and Gleason score > 7 (p < 0.001) as well as tumor size (≥ 20 mm, p = 0.03). In univariate analyses, a high expression of Ki-67 in tumor epithelium was significantly associated with biochemical failure (BF) (digital scoring, p = 0.014) and (visual scoring, p = 0.004). In the multivariate analyses, a high level of Ki-67 was an independent poor prognostic factor for biochemical failure-free survival (BFFS) (Visual scoring, Ki67, p = 0.012, HR:1.50, CI95% 1.10–2.06). In conclusion, high Ki-67 expression is an independent negative prognostic marker for biochemical failure. Our findings support the role of Ki-67 as a significant, poor prognostic factor for in prostate cancer outcome.

Correlation of diffusion MRI with the Ki-67 index in non-small cell lung cancer

BACKGROUND

The primary objective of the study was to evaluate the association between the minimum apparent diffusion coefficient (ADCmin) and Ki-67, an index for cellular proliferation, in non-small cell lung cancers. Also, we aimed to assess whether ADCmin values differ between tumour subtypes and tissue sampling method.

METHODS

The patients who had diffusion weighted magnetic resonance imaging (DW-MRI) were enrolled retrospectively. The correlation between ADCmin and the Ki-67 index was evaluated.

RESULTS

Ninety three patients, with a mean age 65 ± 11 years, with histopathologically proven adenocarcinoma and squamous cell carcinoma of the lungs and had technically successful DW-MRI were included in the study. The numbers of tumour subtypes were 47 for adenocarcinoma and 46 for squamous cell carcinoma. There was a good negative correlation between ADCmin values and the Ki-67 proliferation index (r = -0.837, p < 0.001). The mean ADCmin value was higher and the mean Ki-67 index was lower in adenocarcinomas compared to squamous cell carcinoma (p < 0.0001). There was no statistical difference between tissue sampling methods.

CONCLUSIONS

Because ADCmin shows a good but negative correlation with Ki-67 index, it provides an opportunity to evaluate tumours and their aggressiveness and may be helpful in the differentiation of subtypes non-invasively.

Apparent Diffusion Coefficient (ADC) value: a potential imaging biomarker that reflects the biological features of rectal cancer

Objective

We elected to analyze the correlation between the pre-treatment apparent diffusion coefficient (ADC) and the clinical, histological, and immunohistochemical status of rectal cancers.

Materials and Methods

Forty-nine rectal cancer patients who received surgical resection without neoadjuvant therapy were selected that underwent primary MRI and diffusion-weighted imaging (DWI). Tumor ADC values were determined and analyzed to identify any correlations between these values and pre-treatment CEA or CA19-9 levels, and/or the histological and immunohistochemical properties of the tumor.

Results

Inter-observer agreement of confidence levels from two separate observers was suitable for ADC measurement (k  =  0.775). The pre-treatment ADC values of different T stage tumors were not equal (p  =  0.003). The overall trend was that higher T stage values correlated with lower ADC values. ADC values were also significantly lower for the following conditions: tumors with the presence of extranodal tumor deposits (p  =  0.006) and tumors with CA19-9 levels ≥ 35 g/ml (p  =  0.006). There was a negative correlation between Ki-67 LI and the ADC value (r  =  −0.318, p  =  0.026) and between the AgNOR count and the ADC value (r  =  −0.310, p  =  0.030).

Conclusion

Significant correlations were found between the pre-treatment ADC values and T stage, extranodal tumor deposits, CA19-9 levels, Ki-67 LI, and AgNOR counts in our study. Lower ADC values were associated with more aggressive tumor behavior. Therefore, the ADC value may represent a useful biomarker for assessing the biological features and possible relationship to the status of identified rectal cancers.

Tumor heterogeneity at protein level as an independent prognostic factor in endometrial cancer

Intratumor heterogeneity implies heterogeneous protein function, facilitating tumor adaptation which results in therapeutic failure. We hypothesized that tumor heterogeneity at protein level may influence the course of the disease. As a single biopsy might not represent the full biologic complexity of the tumor, we have analyzed immunohistochemically four different cores obtained from each primary tumor within the cohort of 364 patients with endometrial cancer (EC). The following proteins were examined: estrogen receptor 1 (ESR1), progesterone receptor, epidermal growth factor receptor, v-erb-b2 erythroblastic leukemia viral oncogene homolog 2, receptor tyrosine-protein kinase erbB-3, v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 4, phosphatidylinositol-4,5-bisphosphate 3-kinase, phosphorylated v-akt murine thymoma viral oncogene homolog 1, v-myc avian myelocytomatosis viral oncogene homolog, DNA topoisomerase II alpha 170 kDa (TOP2A), cyclin-dependent kinase inhibitor 2A (CDKN2A), tumor protein p53, RAD21 homolog, S. pombe, and runt-related transcription factor 1. Particularly strong correlation was found between TOP2A and CDKN2A heterogeneity and higher stage of the disease (P = .0002 and P = .0003, respectively). Most correlations with clinicopathologic data were observed for ESR1 heterogeneity that correlated with non-endometrioid carcinomas (P=.02), higher stage (P=.005), grade (P=.01), and the presence of metastases (P = .01). Thirty-nine (11.0%) patients were classified as “globally heterogeneous”. Cumulative tumor heterogeneity strongly correlated with the presence of metastases, higher stage, and higher grade of the disease (all P b .05). It also carried negative prognostic value (P=.0008). We show that the degree of heterogeneity in EC might serve as a clinically valid molecular marker.