Immunoassay and immunohistology studies of chromogranin A as a neuroendocrine marker in patients with carcinoma of the prostate

The value of tumor markers in men with metastatic prostate cancer undergoing [177 Lu]Lu-PSMA therapy

BACKGROUND

Currently, prostate-specific membrane antigen-radioligand therapy (PSMA-RLT) is considered a last-line treatment option in advanced castration-resistant prostate cancer. Despite these patients' poor prognosis, accurate estimation of their overall survival (OS) is essential to determine whether benefits exist from the treatment and whether the loss of valuable time and unnecessary side effects can be avoided. The aim of the present study is to evaluate whether various biochemical markers can predict OS in men undergoing PSMA-RLT and whether the changes assessed after PSMA-RLT correlate with the OS.

METHODS

The tested tumor markers in this retrospective analysis were alkaline phosphatase (ALP), bone-specific alkaline phosphatase (BAP), prostate-specific antigen (PSA), lactate dehydrogenase (LDH), chromogranin A, and pro-gastrin-releasing peptide (pro-GRP). For the evaluation, we performed blood tests before each PSMA-RLT cycle and during follow-up visits (which were 2-3 months apart). All patients were followed up until their deaths. To test the correlations between the tumor markers and survival, we conducted the logrank tests and the multivariate Cox proportional-hazards regression model. The significance level was set at P < .05.

RESULTS

The study included 137 patients who received a total of 487 PSMA-RLT cycles between January 2015 and November 2017. Of the tested biochemical tumor markers, baseline ALP (120 U/L cut-off), LDH (248 U/L cut-off), and PSA (first quartile cut-off) correlated significantly with survival post-PSMA-RLT (P < .001 for ALP and LDH, and P = .007 for PSA). Stable and/or decreased values in most of the initially abnormal parameters were associated with significantly better OS; these parameters were ALP (P = .009), LDH (P = .005), PSA (P < .001), and pro-GRP (P = .013). The BAP and ALP responses also correlated significantly with survival in patients with bone metastases (P = .002 and P < .001, respectively). Furthermore, there was a strong correlation of the kinetic patterns of PSA, ALP, BAP, and LDH with the survival, showing that patients with steadily increasing markers had the shortest OS.

CONCLUSION

Along with the established tumor marker PSA, ALP, LDH, BAP, and pro-GRP were correlated with the OS post-PSMA-RLT in the univariate and multivariate analyses.

Phospholipase D inhibitors reduce human prostate cancer cell proliferation and colony formation

Background:

Phospholipases D1 and D2 (PLD1/2) hydrolyse cell membrane glycerophospholipids to generate phosphatidic acid, a signalling lipid, which regulates cell growth and cancer progression through effects on mTOR and PKB/Akt. PLD expression and/or activity is raised in breast, colorectal, gastric, kidney and thyroid carcinomas but its role in prostate cancer (PCa), the major cancer of men in the western world, is unclear.

Methods:

PLD1 protein expression in cultured PNT2C2, PNT1A, P4E6, LNCaP, PC3, PC3M, VCaP, 22RV1 cell lines and patient-derived PCa cells was analysed by western blotting. PLD1 protein localisation in normal, benign prostatic hyperplasia (BPH), and castrate-resistant prostate cancer (CRPC) tissue sections and in a PCa tissue microarray (TMA) was examined by immunohistochemistry. PLD activity in PCa tissue was assayed using an Amplex Red method. The effect of PLD inhibitors on PCa cell viability was measured using MTS and colony forming assays.

Results:

PLD1 protein expression was low in the luminal prostate cell lines (LNCaP, VCaP, 22RV1) compared with basal lines (PC3 and PC3M). PLD1 protein expression was elevated in BPH biopsy tissue relative to normal and PCa samples. In normal and BPH tissue, PLD1 was predominantly detected in basal cells as well in some stromal cells, rather than in luminal cells. In PCa tissue, luminal cells expressed PLD1. In a PCa TMA, the mean peroxidase intensity per DAB-stained Gleason 6 and 7 tissue section was significantly higher than in sections graded Gleason 9. In CRPC tissue, PLD1 was expressed prominently in the stromal compartment, in luminal cells in occasional glands and in an expanding population of cells that co-expressed chromogranin A and neurone-specific enolase. Levels of PLD activity in normal and PCa tissue samples were similar. A specific PLD1 inhibitor markedly reduced the survival of both prostate cell lines and patient-derived PCa cells compared with two dual PLD1/PLD2 inhibitors. Short-term exposure of PCa cells to the same specific PLD1 inhibitor significantly reduced colony formation.

Conclusions:

A new specific inhibitor of PLD1, which is well tolerated in mice, reduces PCa cell survival and thus has potential as a novel therapeutic agent to reduce prostate cancer progression. Increased PLD1 expression may contribute to the hyperplasia characteristic of BPH and in the progression of castrate-resistant PCa, where an expanding population of neuroendocrine-like cells express PLD1.

Chromogranin A predicts outcome in prostate cancer patients treated with abiraterone

In this retrospective study, we evaluated the chromogranin A (CgA) baseline value as a predictor of clinical outcome in patients with metastatic castration-resistant prostate cancer (CRPC) treated with abiraterone 1000 mg per day, whose disease progressed after docetaxel chemotherapy. In the 48 evaluable patients, serum CgA level was normal when <120  ng/ml (group A, n=16), within three times the upper normal value (UNV) when between 120 and 360 (group B, n=16), more than three times the UNV when ≥360  ng/ml (group C, n=16). Decline in PSA level ≥50% or more (PSA RR) was observed in 26 of 48 (54%) patients. PSA response rate did not correlate with the CgA groups. CgA levels more than three times the UNV predicted an early radiological progressive disease in eight of 11 cases (73%). The median progression-free survival (PFS) among the CgA groups A, B, and C was 9.2, 9.2, and 4.8 months respectively, P=0.0459. The median overall survival (OS) among the CgA groups was 19.0, 18.8, and 10.8 months respectively, P=0.2092. In the multivariate analysis, PSA RR (nonresponsive vs responsive) and CgA levels (group 3 vs groups 1+2) were predictors of PFS (P=0.0002 and P=0.0047 respectively), whereas PSA RR only was significantly associated with OS (P=0.0024), while CgA levels remained of borderline significance (P=0.0919). A serum CGA level more than three times the UNV predicted PFS and showed a trend vs OS prediction, independently from PSA response, in CRPC patients treated with abiraterone.

Neuroendocrine differentiation in castration-resistant prostate cancer: a systematic diagnostic attempt

BACKGROUND

Assessing the neuroendocrine (NE) pattern in castration-resistant prostate cancer (CRPC) may prove useful in selecting potential responders to target therapies such as somatostatin analogues. The aim of this study was to define a panel of markers or examinations appropriate to characterize NE differentiation (NED).

METHODS

Forty-seven patients with CRPC underwent a systematic diagnostic attempt to characterize the NE phenotype using a plasma blood test for chromogranin A (CgA) and immunohistochemical staining of needle biopsy-obtained specimens (CgA, somatostatin receptor 2 [SSTR2], Ki-67, and androgen receptors). In a subgroup of 26 patients, somatostatin receptor scintigraphy using (111)In-DTPA-d-Phe octreotide (octreotide scintigraphy; Octreoscan, Covidien, Hazelwood, MO) was also performed.

RESULTS

NED was found in 85.1% of patients (if serum CgA, tissular CgA, and tissular SSTR2 were considered separately: 54%, 67%, and 58%, respectively). Only 15% of the 26-patient subgroup had an abnormal octreotide scintigraphy result. Although p-CgA and t-CgA were associated with more aggressive disease with a worse prognosis, patients with positive tissular SSTR2 staining had longer overall survival (OS).

CONCLUSION

This systematic approach to explore the NED in a quite homogeneous group of patients with CRPC seems reproducible and appropriate. Further investigations are required to validate this panel and better characterize potential responders to targeted therapy.

Complete remission in a patient with metastatic mixed adenocarcinoma/extrapulmonary small cell carcinoma of the prostate

Approximately 10% of all extra-pulmonary small cell carcinoma (EPSCC) arises in the prostate either as de novo mixed adenocarcinoma with small cell components or a pure small cell carcinoma. Extensive disease carries a median survival of about 10 months in retrospective studies. We present a case managed aggressively with concomitant hormonal and chemotherapy, now 36 months without evidence of disease. At a routine physical, a 55 year male was found to have a 5 cm left upper lobe lung mass, invading his 3rd rib. An FNA revealed an adenocarcinoma of unknown primary. His PSA was elevated to 8 ng/mL and a prostate biopsy revealed Gleason 9 adenocarcinoma with neuro-endocrine/SCC components. A bone scan revealed extensive bone metastasis. He was managed aggressively with concomitant cisplatin, etoposide and hormonal therapy and received 73 Gy of radiation to the prostate. PET scans demonstrated marked response to chemotherapy. PSA and chromogrannin levels down trended to normal limits. His most recent PET scan in July 2010 revealed no evidence of disease and is in remission. We present a unique case of metastatic mixed adenocarcinoma/SCC of the prostate, in which the patient survived more than 36 months with complete remission after initiation of aggressive hormonal and chemotherapy. Data on survival in this patient population is limited to case reports, and ordinarily carries a poor prognosis of less than 1 year. In patients with clinical and pathologic features of mixed disease, initiation of early multi-modal therapy is warranted. Additionally, it may be of prognostic significance to biopsy any metastatic lesion.

Assessment of serum chromogranin-A as prognostic factor in high-risk prostate cancer

PURPOSE

The presence of neuroendocrine differentiation may play a key role in androgen-independent tumor progression. The prognostic significance of plasma chromogranin-A (CgA) was assessed in a series of consecutive patients with high-risk prostate cancer (PCa).

PATIENTS AND METHODS

Twenty-three patients presenting high-risk PCa and 8 healthy individuals, as control group, had their blood samples collected to evaluate CgA, free and total prostate specific antigen, and free and total testosterone in a pilot study. The correlations of serum CgA levels with PSA, testosterone, Gleason score, number of foci of hypercaptation in bone scan, age, and outcomes were evaluated at baseline and after 12 months.

RESULTS

Patients with PCa had significantly higher levels of plasma CgA (mean, 8.7; range, 1.9-73) than healthy patients (mean, 3.45; range, 0.6-5.6), P = 0.02. Analyzing only the patients group through correlation of the ranks, it was observed that CgA has low, insignificant correlations with PSA (P = 0.07) and with metastatic extension (P = 0.09). No association was found between the plasma CgA levels and the Gleason score (P = 0.20), age (P = 0.15), or disease progression (P = 0.27).

CONCLUSION

The serum levels of CgA were significantly increased in the group with PCa compared with the healthy group. However, there were low correlations between serum CgA and known prognostic factors (such as total and free PSA, age, Gleason score, and bone metastases) or clinical deterioration. Although future studies are needed with larger samples and longer follow-up, the presented data envisage a limited role to serum CgA as high-risk PCa prognostic factor.

Implications of circulating chromogranin A in prostate cancer

OBJECTIVE

To evaluate whether measurement of circulating chromogranin A (CgA) levels provides clinicopathological and prognostic information in prostate cancer.

MATERIAL AND METHODS

Plasma CgA levels were measured in 57 patients with histologically confirmed prostate cancer (stage B or less, n=22; stage C, n=10; stage D1, n=2; hormone-naive D2, n=12; hormone-refractory D2, n=11) and in 22 with undetected prostate cancer using an enzyme-linked immunoabsorbent assay.

RESULTS

Median plasma CgA levels were significantly higher in patients with prostate cancer than in those with undetected cancer (p=0.0271). Higher stage (p<0.0001) and higher grade (p=0.0412) tumours were also significantly associated with higher plasma CgA levels. Above-normal CgA levels were also detected in 4/27 patients (15%) who underwent radical prostatectomy. Postoperative clinical failure was not reported in the prostatectomy patients; however, prostate-specific antigen (PSA) failure was reported in 44% of patients after a median follow-up period of 20.3 months. Multivariate analysis revealed that the pathological stage of the tumour was the only independent predictive variable for postoperative PSA failure (p=0.0494). Preoperative plasma CgA levels had no impact on postoperative PSA failure in the subgroup (prostatectomy patients). Elevated plasma CgA levels were associated with a poor survival prognosis in patients with stage D2 prostate cancer after a median follow-up period of 22.5 months (p=0.0416).

CONCLUSIONS

It was demonstrated in this study that plasma CgA levels in prostate cancer increase with the severity of the disease, especially for progressive hormone-refractory prostate cancer (HRPC), after hormone therapy. Although this cross-sectional study involved only a small number of patients, we believe that plasma CgA levels may effectively predict HRPC status and prognosis in metastatic cases.

The impact of diet and micronutrient supplements on the expression of neuroendocrine markers in murine Lady transgenic prostate

BACKGROUND

Neuroendocrine (NE) differentiation (NED) in prostate cancer (PCa) is associated with morbidity and death; however, the underlying cause(s) promoting NED in PCa have yet to be determined. In this study, we examined the effect of both diet and micronutrient supplementation on the expression of NE markers using the Lady (12T-10) transgenic model of PCa. Lady (12T-10) transgenic animals develop advanced adenocarcinoma with NE characteristics that exhibits metastases in approximately 80% of cases. In this model a high fat diet has been shown to increase the severity of disease, while the use of micronutrients can inhibit this progression.

METHODS

In this study we used immunohistochemical analysis to determine expression of the NE markers: chromogranin A (CgA), neuron-specific enolase (NSE), bombesin, parathyroid hormone-related peptide (PTHrP), neurotensin and serotonin in prostates of PCa-bearing Lady (12T-10) mice.

RESULTS

High fat diet was correlated with significantly elevated expression of CgA and serotonin in prostate tissue of Lady (12T-10) mice. Addition of micronutrients to the control and high fat diet reproducibly elevated PTHrP and bombesin expression and suppressed NSE expression, while prostate tissue from the control diet supplemented with micronutrients exhibited significantly lower numbers of calcitonin- and neurotensin-positive cells.

CONCLUSIONS

These results highlight the importance of dietary control in management of disease and identify differential changes in NE marker expression, which may be diagnostically viable in monitoring the impact of therapies on disease status.

Processing-independent quantitation of chromogranin a in plasma from patients with neuroendocrine tumors and small-cell lung carcinomas

BACKGROUND

Most neuroendocrine tumors express chromogranin A (CgA). The posttranslational processing of neuroendocrine proteins such as CgA is often specific for the individual tumor. To cope with this variability and improve tumor diagnosis, we developed a processing-independent analysis (PIA) method to measure the total CgA product.

METHODS

For PIA, samples underwent trypsin treatment followed by measurement of CgA by the "CgA(340-->)" assay, in which the antiserum binds an epitope starting at amino acid 340 of CgA and including amino acid residues located in the C-terminal direction. The diagnostic accuracy of the CgA PIA and 3 sequence-specific assays for CgA were evaluated on plasma samples from patients with neuroendocrine tumors and small-cell lung carcinomas. Furthermore, we investigated whether the CgA plasma concentrations correlated with the tumor burden.

RESULTS

Size-exclusion chromatography of plasma showed that CgA immunoreactivity mainly consisted of high-molecular-weight forms, indicating that neuroendocrine tumors may secrete large amounts of poorly processed CgA. Accordingly, trypsination of plasma from 54 patients with neuroendocrine tumors or small-cell lung carcinomas increased the CgA(340-->) immunoreactivity up to 500-fold. Both the CgA(340-->) assay and the PIA measured significantly higher plasma concentrations in patients with very extensive disease than in patients with less widespread disease. The diagnostic sensitivity was 0.91 when using the CgA(340-->) assay and 0.82 using the CgA PIA.

CONCLUSION

The CgA(340-->) assay and CgA PIA are both useful for diagnosis of neuroendocrine tumors and small-cell lung carcinomas and both assays correlate with tumor burden.

Q RT-PCR detection of chromogranin A: a new standard in the identification of neuroendocrine tumor disease

OBJECTIVE

Message and protein expression of CgA was examined to evaluate the sensitivity of a PCR-based approach in the detection of covert neuroendocrine (NE) tissue.

SUMMARY BACKGROUND DATA

Immunohistochemical (IHC) measurement of chromogranin A (CgA) discriminates gastrointestinal (GI) carcinoids from epithelial tumors. IHC is, however, an insensitive technique to identify micrometastases or delineate subpopulations of NE cells.

METHODS

CgA gene expression was examined by Q-RT PCR in GI carcinoids (small intestinal and metastases, n=17, gastric, n=5), appendiceal tumors (n=10), and adenocarcinomas (gastric, n=5, colorectal, n=6). CgA protein expression levels were quantitatively analyzed following IHC by automated quantitative analysis (AQUA) in 2 tissue microarrays (GI carcinoid and GI adenocarcinoma).

RESULTS

CgA gene was overexpressed (P<0.001) in GI carcinoids compared with GI adenocarcinomas and normal mucosa. Elevated levels (P<0.00001) were also identified in carcinoid liver and lymph node (LN) metastases. CgA levels were higher (approximately 2-4-fold) in NE appendiceal carcinoids than in adenocarcinoids, but in GI adenocarcinomas were identical to normal mucosa. Histologically normal lymph nodes expressed detectable CgA message in 30% of cases. CgA protein levels were highest in primary GI carcinoids and in liver metastases and significantly elevated (P<0.005) compared with nonmetastatic lesions. Expression in liver and LN metastases was significantly elevated (P<0.000001) compared with normal. Analysis of mRNA by Q-RT PCR was >200-fold more sensitive than by IHC.

CONCLUSIONS

Overexpression of CgA mRNA and protein in GI carcinoids can identify metastatic cells; thus, PCR for CgA can be used to identify micrometastases not evident by light microscopy or IHC as well as define tumors of ambivalent morphologic phenotype. The use of this sensitive strategy to assess NETs and apparently normal LNs and liver may be of future utility in defining therapeutic strategy.

Evaluation of Chromogranin A Expression in Patients with Non-Neuroendocrine Tumours

BACKGROUND

Chromogranin A (CgA) is well established as a serum marker for neuroendocrine tumours and has also been associated with some non-neuroendocrine tumours, suggesting a possible role for somatostatin analogues such as octreotide in the treatment of these tumours.

OBJECTIVE

The aim of this study was to measure plasma CgA levels in patients with various non-neuroendocrine tumours in order to identify those patients who might benefit from octreotide therapy.

METHODS

Plasma CgA levels were tested in 151 patients with metastatic non-neuroendocrine tumours. Patients with highly elevated levels were assessed by OctreoScan scintigraphy to determine their somatostatin receptor status, and those with positive results were offered treatment with the somatostatin analogue octreotide, 20 mg every 4 weeks, and followed up every 3 months.

RESULTS

CgA levels were elevated (>18 U/L) in 34/72 patients with breast cancer, 11/21 with lung cancer, 10/28 with gastrointestinal cancer, 7/12 with gynaecological cancer, 6/9 with genitourinary cancer, 5/5 with haematological cancer, and 3/4 with head and neck cancer. Eight patients with CgA levels >150 U/L underwent scintigraphy, five of whom (two colorectal, two prostate, one non-small cell lung cancer [NSCLC]) showed positive results and received treatment with octreotide. Follow-up for a mean 12-16 months showed improvements in biochemical parameters, cenesthesis and quality of life.

CONCLUSION

CgA levels were found to be elevated in approximately 50% of patients with non-neuroendocrine tumours. Further studies are required to determine the value of CgA as a marker for non-neuroendocrine tumours and the role of somatostatin analogues as a treatment for these tumour types.

Prognostic significance of plasma chromogranin a levels in patients with hormone-refractory prostate cancer treated in Cancer and Leukemia Group B 9480 study

OBJECTIVES

To test the hypothesis that chromogranin A (CgA) levels are prognostic in patients with metastatic hormone-refractory prostate cancer (HRPC). The extent of neuroendocrine differentiation in prostate cancer correlates with aggressive disease and with progression to HRPC. Plasma CgA levels in patients with prostate cancer may reflect the extent of the tumor neuroendocrine phenotype.

METHODS

Pretreatment plasma was collected from 390 patients with metastatic HRPC enrolled in the Cancer and Leukemia Group B (CALGB) 9480 trial, a study of three different doses of suramin. Plasma CgA levels were determined in 321 samples in duplicate using a quantitative sandwich immunoassay. The proportional hazards model was used to assess the prognostic significance of CgA in predicting overall survival.

RESULTS

The median plasma CgA level was 12 U/L (interquartile range 7.7 to 19.3). In univariate analysis, plasma CgA correlated inversely with survival times, with a survival time of 17 months for low CgA (less than 12 U/L, 95% CI 14 to 19) compared with 11 months for high CgA (95% CI 8 to 14, P = 0.014) and at all exploratory cutpoints, including CgA of 9.5 U/L or less versus greater than 9.5 U/L, with survival of 19 months compared with 12 months (P = 0.0015). In multivariate models (adjusting for performance status, prostate-specific antigen, and lactate dehydrogenase), the plasma CgA levels remained predictive of overall survival.

CONCLUSIONS

These results support the hypothesis that serum CgA levels correlate with outcome in patients with HRPC, although the clinical significance needs to be established in confirmatory studies before incorporation of CgA measurements in clinical practice.

Surgical treatment of non-functioning pancreatic islet cell tumors

Pancreatic endocrine tumors (PETs) are rare neoplasms originating from the amine precursor uptake and decarboxylation (APUD) stem cells. Although the majority of PETs are sporadic, they frequently occur in familial syndromes. PETs may cause a variety of functional syndromes or symptoms of local progression if they are non-functional. General neuroendocrine tumor markers are highly sensitive in the diagnostic assessment of a PET. Imaging studies for tumor localization and staging include computer tomography (CT) scan, magnetic resonance imaging (MRI), In(111)-octreotide scan, MIBG, and endoscopic ultrasonography (EUS). Treatment of PETs often requires a multi-modality approach; however, surgical resection remains the only curative therapy for localized (non-metastatic) disease. Treatment of metastatic disease includes biologic agents, cytotoxic chemotherapy, and liver-directed therapies.

Neuroendocrine differentiation in prostate cancer

BACKGROUND

In numerous recent studies attention has been focused to neuroendocrine differentiation (NED) in prostate cancer (PC). Focal NED is present in almost all PCs, but it is prominent in only 5-10% of the carcinomas. The prognostic significance of focal NED in PC is controversial, but current evidence suggests its influence on the onset and/or conversion of hormone resistant tumor phenotype. The aim of this study was to evaluate the relationship between NED status, based only on immunohistochemical use of neuroendocrine (NE) markers, with PC grade and stage, and preoperative serum levels of prostate-specific antigen (PSA).

METHODS

The study included the biopsy material of 73 untreated PC patients (pts.) obtained by transurethral resection (TUR) (37 pts.), and radical retropubic prostatectomy (RRP) (36 pts.). Two representative tissue samples (typically the block containing the largest amount of neoplasm) were selected for immunohistochemical (IMM) staining. NE cells were identified using a panel of IMM markers: chromogranin A, neuron-specific enolase, and serotonin. The level of PC exocrine differentiation was detected by monoclonal antibodies against PSA.

RESULTS

Significant expression of NE cells was demonstrated in 26 (70.2%) pts. with PC after TUR. In this group, serum preoperative PSA values ranged from 0.1 to 9.6 ng/ml. The majority of pts. with NED had low differentiated PC with Gleason grade score (GGS) > 7, and normal PSA values below 4 ng/ml (77%), in clinical stage D (54%). Statistically significant correlation (p<0.01) of positive NED with higher stage and grade and low PSA values was established. Among the pts. with localized PC in whom RRP was performed (n=36), significant expression of NE cells was found in 15 pts. (41.7%), 8 (53.3%) in pT2 stage, and 7 (46.7%) in pT3 stage. Significant correlation between NED with preoperative PSA values and stage of PC in pts. with RRP was not found.

CONCLUSION

We demonstrated the significant NED in poorly differentiated PC in patients in the advanced stage of the disease. The expression of NED in organ-confined PC did not correlate with tumor stage, but it correlated with tumor grade (GGS < or = 7).

Neuroendocrine differentiation in hormone refractory prostate cancer following androgen deprivation therapy

OBJECTIVE

To evaluate the relationship between neuroendocrine differentiation (NED) status and hormone refractory prostate cancer (HRPC) following hormone therapy based on immunohistochemical study.

METHODS

Seventy-two prostate cancer specimens obtained at radical prostatectomy and 21 prostate cancer autopsy specimens from patients who died from HRPC after androgen deprivation therapy were examined for NED status using an antibody against chromogranin A. These specimens were classified into 3 arms: 38 radical prostatectomy specimens from patients with no neoadjuvant hormone therapy (Group 1); 34 from patients with neoadjuvant hormone therapy for 3 to 6 months (Group 2); and 21 autopsy specimens from patients with HRPC following androgen deprivation therapy for more than 1 year (Group 3). Staining of prostatic carcinoma was scored as: 0 = no staining; 1 = staining cells <10%; 2 = staining cells 10-20%; and 3 = staining cells >20%. Differences in scores among the groups were compared using the Kruskal-Wallis rank test. Multivariate analysis using a logistic regression model was performed to examine whether NED status was associated with pathological stage (pT), grade and group.

RESULTS

Forty-nine (53%) tumors had CgA stained cells. NED status increased with longer duration of hormone therapy (p<0.0001). The mean staining score (and standard deviation) was 0.4+/-0.7 in Group 1, 0.7+/-0.7 in Group 2, and 1.4+/-1.1 in Group 3, respectively. By multivariate analysis Group 3 had a relative risk of 5.46 (95%CI 1.28-23.29) for NED compared to the other groups. But other variables were not related to NED. HRPC following Long-term hormonal therapy was the only independent predictor of NED.

CONCLUSIONS

The results of this study demonstrated that NED status was significantly increased in patients with HRPC following long-term androgen deprivation therapy, but it could not be discriminate whether the increase of NED is attributable to condition of hormone refractoriness or long-term hormonal therapy.

Detection of Prostate Cancer and Predicting Progression

Carcinoma of the prostate is the second leading cause of male cancer-related death in the United States. Better indicators of prostate cancer presence and progression are needed to avoid unnecessary treatment, predict disease course, and develop more effective therapy. Numerous molecular markers have been described in human serum, urine, seminal fluid, and histological specimens that exhibit varying capacities to detect prostate cancer and predict disease course. However, to date, few of these markers have been adequately validated for clinical use. The purpose of this review is to examine the current status of these markers in prostate cancer and to assess the diagnostic potential for future markers from identified genes and molecules that display loss, mutation, or alteration in expression between tumor and normal prostate tissues. In this review we cite 91 molecular markers that display some level of correlation with prostate cancer presence, disease progression, cancer recurrence, prediction of response to therapy, and/or disease-free survival. We suggest criteria to consider when selecting a marker for further development as a clinical tool and discuss five examples of markers (chromogranin A, glutathione S-transferase pi 1, prostate stem cell antigen, prostate-specific membrane antigen, and telomerase reverse transcriptase) that fulfill some of these criteria. Finally, we discuss how to conduct evaluations of candidate prostate cancer markers and some of the issues involved in the validation process.

Analysis of biochemical bone markers as prognostic factors for survival in patients with hormone-resistant prostate cancer and bone metastases

OBJECTIVES

To investigate the prognostic value of some conventional bone markers and a number of other factors in terms of the survival of patients with hormone-resistant prostate cancer and bone metastases treated with chemotherapy.

METHODS

The data of 141 patients were analyzed to verify the influence of the following factors on survival: bone-alkaline phosphatase, type I collagen propeptide, the carboxyterminal telopeptide of type I collagen, the urinary calcium/creatinine ratio, patient age, Karnofsky performance status, pathologic grade, duration of response to primary hormonal therapy, prostate-specific antigen, hemoglobin, lactate dehydrogenase, and extent of bone disease.

RESULTS

When all the variables were simultaneously analyzed using the multivariate proportional hazard model, only Karnofsky performance status (P <0.005) and duration of response to primary hormonal therapy (P <0.0001) remained statistically significant.

CONCLUSIONS

The results of this study suggest that bone-alkaline phosphatase, type I collagen propeptide, the carboxyterminal telopeptide of type I collagen, and the urinary calcium/creatinine ratio are not prognostic of survival in patients with hormone-resistant prostate cancer and bone metastases treated with chemotherapy.

Somatostatin receptors: from basic science to clinical approach. Unlabeled somatostatin analogues-1: Prostate cancer

Neuroendocrine cells have been found in all the stages of prostate cancer, but their clinical significance is not completely understood. Neuroendocrine cells are androgen receptor- and prostate-specific antigen-negative, do not proliferate, and secrete many neuropeptides, such as chromogranin A. Neuroendocrine differentiation of prostate cancer correlates with an advancing tumour stage, poor prognosis and tumour progression after androgen deprivation. Furthermore, neuroendocrine phenotype is associated with the increased expression of neo-angiogenesis and vascular endothelial growth factor and with an over-expression of survivin, a new anti-apoptosis protein. Chromogranin A is the quantitatively major secretory protein of the vesicles inside neuroendocrine prostate cells and it is the marker most frequently used to detect neuroendocrine features, both in tissues and in general circulation. Tumours displaying neuroendocrine phenotype tend to be more aggressive and resistant to hormone-therapy. Neuroendocrine differentiation seems to be a dynamic phenomenon: in vitro and in vivo data suggest that it can be induced by androgen suppression. Moreover, the differences in the expression of somatostatin receptors between primary and hormone-refractory prostate cancer are likely to be related to the changes in neuroendocrine phenotype during androgen deprivation. Circulating chromogranin A levels seem to be scarcely affected by endocrine- and chemotherapy, while they significantly decreased after treatment with somatostatin analogs.

Human prostate cancer risk factors

Prostate cancer has the highest prevalence of any nonskin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating androgens will develop microscopic prostate cancer if they live long enough. This review is a contemporary and comprehensive, literature-based analysis of the putative risk factors for human prostate cancer, and the results were presented at a multidisciplinary consensus conference held in Crystal City, Virginia, in the fall of 2002. The objectives were to evaluate known environmental factors and mechanisms of prostatic carcinogenesis and to identify existing data gaps and future research needs. The review is divided into four sections, including 1) epidemiology (endogenous factors [family history, hormones, race, aging and oxidative stress] and exogenous factors [diet, environmental agents, occupation and other factors, including lifestyle factors]); 2) animal and cell culture models for prediction of human risk (rodent models, transgenic models, mouse reconstitution models, severe combined immunodeficiency syndrome mouse models, canine models, xenograft models, and cell culture models); 3) biomarkers in prostate cancer, most of which have been tested only as predictive factors for patient outcome after treatment rather than as risk factors; and 4) genotoxic and nongenotoxic mechanisms of carcinogenesis. The authors conclude that most of the data regarding risk relies, of necessity, on epidemiologic studies, but animal and cell culture models offer promise in confirming some important findings. The current understanding of biomarkers of disease and risk factors is limited. An understanding of the risk factors for prostate cancer has practical importance for public health research and policy, genetic and nutritional education and chemoprevention, and prevention strategies.

Differential effect of chromogranin A fragments on invasion and growth of prostate cancer cells in vitro

OBJECTIVES

To investigate the effect of various chromogranin A (CgA) fragments on the invasion, haptotactic migration, and growth of prostate cancer cells.

METHODS

We investigated the effect of five kinds of CgA fragments (79-115, 286-301, 324-341, 344-374, and 356-374) on the invasion of PC-3 and DU-145 prostate cancer cells through a reconstituted basement membrane (matrigel) and the haptotactic migration of these cells using a Transwell cell culture chamber assay. Cell growth was assessed by the WST-1 Cell Counting Kit.

RESULTS

CgA (79-115) inhibited the invasive ability of PC-3 and DU-145 cells (P = 0.035 and P = 0.037, respectively). CgA (79-115) also inhibited the haptotactic migration of these cells (P = 0.031 and P = 0.021). On the other hand, other CgA fragments had no significant effect. CgA (79-115) also inhibited the cell growth of PC-3 cells (P = 0.012) and DU-145 cells (P < 0.001). CgA (324-341), CgA (344-374), and CgA (356-374) inhibited the cell growth of DU-145 cells (P < 0.001, P < 0.001, and P < 0.001, respectively).

CONCLUSIONS

These results indicate that some CgA fragments may affect the invasion and growth of prostate cancer cells.

A comparative study of prostate specific antigen (PSA), C-terminal propeptide of blood type I procollagen (PICP) and urine type I collagen-crosslinked N telopeptide (NTx) levels using bone scintigraphy in prostate cancer patients

We compared the ability to diagnose skeletal metastasis between serum prostate specific antigen (PSA), C-terminal propeptide of blood type I procollagen (PICP), and urine type I collagen-crosslinked N telopeptide (NTx) in prostate cancer patients. In sixty-nine patients with prostate cancer, bone scintigraphy was performed, and serum PSA and PICP and urine NTx were measured. The median level of serum PSA in the osseous metastasis-negative group (n = 33) was 0.80 ng/ml being significantly lower as compared to the osseous metastasis-positive group (n = 36, 7.70 ng/ml) (p < 0.0001). The serum PICP and urine NTx/Cr levels appeared lower in the osseous metastasis-negative group than the osseous metastasis-positive group, but there was no significant difference. Logistic regression analysis showed that ability to diagnose skeletal metastasis of serum PSA was 68.1% and superior to those of serum PICP (56.5%) and urine NTx/Cr (53.6%). Serum PSA improved the ability to diagnose skeletal metastasis when combined with serum PICP or urine NTx/Cr. When patients were grouped according to the extent of disease grade (EOD grade) nomenclature, Spearman's correlation coefficient by rank showed that serum PSA was most significantly correlated with EOD grade (p < 0.0001). In 14 patients whose skeletal metastases progressed or regressed, the change of serum PSA more clearly separated the osseous metastasis-regression group and osseous metastasis-progression group than did serum PICP and urine NTx/Cr. Serum PSA was more reliable than bone resorption and formation markers produced by crosslinking of type I collagen.

A prostate-derived cDNA that is mapped to human chromosome 19 encodes a novel protein

The epithelial cells of prostate gland secrete various secretory products that play an important role in the growth and differentiation of prostate gland. These secretory products have also been implicated in neuroendocrine differentiation of benign prostatic hyperplasia and prostate malignancy. We have cloned a prostate-derived cDNA encoding a novel protein with a predicted molecular weight of 78 kDa (P(78)), and precisely mapped the cDNA sequence to chromosome 19. The P(78) gene has a complex genomic structure with 18 exons and 17 introns. The P(78) contains two conserved structural domains with limited similarity to domain D of synapsin I. The P(78) mRNA was expressed in various human cell lines. Western blot analysis using antibody specific for the P(78) revealed the presence of the P(78) protein in the prostate cancer cell lines with much lower level in metastatic prostate cancer cell lines compared to that in a primary prostate cancer cell line.

Prostatic adenocarcinoma metastases mimicking small cell carcinoma on fine-needle aspiration

Prostate adenocarcinoma (PA) is known to metastasize widely to bone, lung, lymph nodes, and other sites. We have observed a rare, although distinctive, neuroendocrine (NE) cytomorphology of metastatic PA on fine-needle aspiration (FNA) that mimics small cell carcinoma (SCC). From a total of 117 cases, eight cases of metastatic PA diagnosed on FNA showed cytomorphologic features indistinguishable from SCC. All specimens were reviewed, along with immunoperoxidase (IPOX) studies using prostate specific (PSA, PSAP) and NE markers (synaptophysin, chromogranin, etc.). The patients ranged in age from 51-68 (mean age = 63). The PSA levels at the time of FNA ranged from <0.1 to 2,892 ng/ml (normal postprostatectomy <0.2 ng/ml). Sites of FNA included liver (two), soft tissue (five), and lymph node (one). FNA was performed from 11 mo to 6 yr after the initial diagnosis of the primary tumor. All primary PA were of high Gleason grade ranging from 7-9. None of the primary PA showed neuroendocrine morphology. Cytomorphologic characteristics observed on FNA included predominantly single cells with occasional sheets or loose cell aggregates. A predominant NE nuclear morphology was evident (i.e., hyperchromasia, fine dusty chromatin, inconspicuous nucleoli, nuclear molding, chromatinic crush artifact, karyorrhexis, mitoses, etc.), with none of the tumors displaying glandular formation. Taken together, these features gave these metastases a cytomorphology indistinguishable from SCC. IPOX studies revealed PSA-positivity (5/7), PSAP-positivity (4/7), and only focal NE markers positivity (3/6). Metastatic prostate carcinoma may rarely mimic a SCC (6.8% in this study). This often necessitates further patient workup to identify the primary source for the patient's metastasis, particularly if the patient has multiple lesions. An accurate diagnosis of these lesions as PA metastases is essential for effective, timely treatment and therapeutic design.

Potential clinical value of circulating chromogranin A in patients with prostate carcinoma

BACKGROUND

Neuroendocrine (NE) differentiation of prostate adenocarcinoma has received increasing attention in recent years as a result of possible implications for prognosis and therapy. The presence of NE tumor subpopulation can be gauged non invasively by measuring circulating levels of secretory products, primarily chromogranin A (CgA).

METHODS

This article provides a review on published papers evaluating circulating CgA in prostate cancer patients.

RESULTS

Circulating CgA levels were found to be higher in prostate cancer patients than in patients with benign or pre-malignant prostatic diseases. In patients with malignancy, they correlated either to the stage of disease or to the condition of hormone refractoriness. CgA levels did not correlate with serum prostate specific antigen (PSA) and were supranormal in the majority of advanced patients with PSA within normality. In hormone refractory cases, elevated CgA was a significant predictor of poor prognosis, independently from serum PSA. CgA values were not substantially affected by either endocrine therapy or chemotherapy. They were found to increase during androgen deprivation in some cases and this trend preceded that of PSA. The administration of a somatostatin analog in hormone refractory cases was able to reduce plasma CgA values consistently.

CONCLUSIONS

Present data suggest a potential role of circulating CgA in the management of prostate cancer patients. CgA determination may be useful diagnostically and prognostically and could offer complementary information with respect to PSA. Serial evaluation of circulating CgA could provide information on changes in the NE phenotype expression as a consequence of tumor progression and/or treatment administration.

Relationship between neuroendocrine features and prognostic parameters in human prostate adenocarcinoma

PURPOSE

The biological behaviour of prostate cancer is highly variable and prediction by the commonly employed prognostic parameters is not sufficient. The concept of neuroendocrine (NE) differentiation in prostate adenocarcinoma has recently received increasing attention due to possible implications for prognosis and therapy.

MATERIALS AND METHODS

Core needle biopsies from 142 newly diagnosed patients were immunohistochemically examined for the coexistence of NE differentiation using an antibody against chromogranin A (CgA). Circulating CgA was available in 106 of these patients.

RESULTS

NE differentiation was found in 64 (45.1%) tumors. Among them 29 (20.4%) had CgA positive cells scattered or focally distributed in less than 5% per mm3 of tumor tissues, 26 (18.3%) between 5% and 10% and 9 (6.4%) more than 10%, respectively. There was a significant correlation between the extent of NE features and either Gleason score (P < 0.01) or stage of disease. Circulating CgA but not PSA correlated with immunohistochemical CgA (P < 0.03) particularly in metastatic cases.

CONCLUSIONS

These data support the concept that NE differentiation in human prostate cancer has a negative prognostic significance. Circulating CgA levels reflect immunohistochemical findings.

Serum chromogranin-A in advanced prostate cancer

OBJECTIVE

To determine the value of serum chromogranin A (CgA), a marker of neuroendocrine differentiation, for monitoring prostate cancer: CgA levels were related to three other tumour markers, i.e. total prostate-specific antigen (tPSA), prostatic acid phosphatase (PAP), neurone-specific enolase (NSE), and to testosterone, to assess the importance of hormone withdrawal.

PATIENTS AND METHODS

Serum samples (218) were obtained from 118 patients with prostate cancer, including 111 patients with advanced prostate cancer: 103 presented to our centre for systemic radionuclide therapy of painful skeletal metastases. CgA concentrations were measured using a new immunoradiometric assay (IRMA: Cis Bio International, Gif sur Yvette, France) and a threshold of 70 ng/mL was determined after receiver operating characteristic curve analysis. Testosterone was also measured with an IRMA assay; tPSA, PAP and NSE were assayed using the time-resolved amplified cryptate emission.

RESULTS

Serum marker levels were high in 64% of the patients for CgA, 24% for NSE, 89% for tPSA and 81% for PAP. Patients resistant to endocrine treatments and with elevated tPSA (i.e. hormone-independent) showed increased CgA and NSE in 62% and 29%, respectively. Patients with hormone-dependent prostate cancer (i.e. with a normal tPSA level) had elevated CgA in 59% but no abnormal NSE. All patients of the latter group except one showed clinical progression of their disease. However, the mean (SD) concentrations of CgA in hormone-independent (146) or hormone-dependent (22) patients, at 185.3 (449.1) and 160.9 (293.9) ng/mL, respectively, were not statistically different (P=0.8, Mann-Whitney U-test). For 30 patients, blood samples were drawn and markers measured before and after systemic radionuclide therapy. There was a significant increase in the CgA and tPSA concentrations after treatment (P=0.0146 and 0.0025, respectively).

CONCLUSIONS

In association with tPSA, serum CgA appears to be a promising marker for monitoring patients with prostate cancer.

Neuroendocrine tumor markers

Tumor markers used in the diagnosis and follow-up of patients with neuroendocrine tumors are in most instances not specific for a given tumor and circulate under normal conditions in the serum, making their use as an early diagnostic tool difficult (low sensitivity). By combining hormone measurements with tissue responsiveness, demonstrations of inappropriate secretions of PTH, insulin, and gastrin during hypercalcemia, hypoglycemia, and hyperacidity, respectively, become highly sensitive and specific diagnostic tests. The application of polyclonal antibodies in RIAs of hormones, such as ACTH, insulin, and gastrin, increase the diagnostic level of hormone measurements in patients with neuroendocrine tumors. Other markers, such as chromogranin A, neuron-specific enolase, and alpha-subunit, as well as peptide receptor visualization, are of increasing importance in the diagnosis and follow-up of neuroendocrine and non-neuroendocrine tumors.

Progression of prostate cancer to neuroendocrine cell tumor

BACKGROUND

The progression to endocrine therapy-resistant prostate cancer is partly due to clonal change to neuroendocrine cell tumor. To elucidate this pathologic process, the clinical courses of four cases of neuroendocrine cell tumor that were found at autopsy are reported.

METHODS

Between 1995 and 1999, autopsies were performed for 20 cases of prostate cancer. Lesions predominantly composed of a neuroendocrine cell tumor (small cell carcinoma) were found in four men. The clinical courses of these cases were compared to 16 other non-neuroendocrine cell tumors (adenocarcinomas).

RESULTS

The outstanding features of the neuroendocrine cell tumors were: (i) survival was brief after relapse, although the duration of control by employing endocrine therapy varied; (ii) the prostate-specific antigen level did not increase after relapse; and (iii) the sites of metastasis were similar to those of common adenocarcinomas.

CONCLUSION

The progression to a neuroendocrine cell tumor indicated a poor prognosis and slight (if any) changes in the serum prostate-specific antigen level. This tumor might not appear to respond to any therapeutic attempt.

Neuroendocrine cells in human prostate over-express the anti-apoptosis protein survivin

BACKGROUND

Neuroendocrine (NE) differentiation may be related to the growth and progression of prostate cancer, especially androgen-insensitive tumors. Recently the over-expression of a new anti-apoptosis protein, survivin, has attracted attention for its potential implication in many human cancers. The fact that NE cells in prostate are bcl-2 negative prompted us to investigate if the prostatic NE cells over-express survivin.

METHODS

Double immunohistochemical staining and immunofluorescence of chromogranin A (CgA) and survivin were performed in 57 patients with localized prostate cancer who underwent radical prostatectomy. The terminal deoxynucleotidyl transferase (TDT)-mediated dUTP-digoxigenin nick end-labeling (TUNEL) method was used for apoptosis detection in three prostate cancer specimens with NE differentiation. The relationship between NE differentiation and clinicopathological characteristics, disease progression as well as patient survival, were analyzed retrospectively.

RESULTS

It was found that NE cells in both benign and malignant prostate tissues over-expressed the anti-apoptosis protein survivin. While apoptosis was detected in non-NE epithelial cells, all NE cells were negative for apoptosis detection. During the period of follow-up, 17 (63%) of 27 patients with NE differentiation had prostate cancer progression, while 12 (40%) of 30 patients without NE differentiation had systemic prostate cancer progression. 10 (37%) of 27 patients with NE differentiation died from prostate cancer during the period of follow up, while 6 (20%) of 30 patients without NE differentiation died from prostate cancer. However, none of these characteristics reached statistical significance, probably because of the small number of cases enrolled.

CONCLUSIONS

This study discovers that all the prostatic NE cells express the new anti-apoptosis protein survivin. This provides a strong molecular basis for the hypothesis that NE cells may endure stressful conditions and escape from apoptosis. While our results suggest a trend of NE differentiation with poorer prognosis, the prognosis implication cannot be concluded due to our small sample size.

Prognostic value of neuroendocrine serum markers and PSA in irradiated patients with pN0 localized prostate cancer

BACKGROUND

The prognosis of patients with localized prostate cancer depends on clinical stage, histological grade, and pretreatment prostate-specific antigen (PSA). We evaluated the additional prognostic impact of serum levels of neuron-specific enolase (NSE) and chromograninA (CgA) after curative radiotherapy and the importance of serum PSA, analyzed 3 months after irradiation.

METHODS

From 1988 to 1995, 161 patients with localized T1-4, pN0M0, prostate adenocarcinoma were treated with external radiation (66Gy, 2Gy/5 fractions per week). Frozen serum samples were assessed for CgA, NSE, and PSA before and 3 months after radiotherapy. CgA was analyzed in only 100 patients. NSE and CgA were determined by a immunometric assay. Total PSA was measured by a time-resolved fluoro-immunometric assay.

RESULTS

Prior to radiotherapy CgA was elevated in 16 of 100 patients, and NSE was elevated in 33 of the 161 patients. There was no association between grade, T category or pretreatment PSA and the levels of neuroendocrine markers. Pretreatment-elevated serum NSE, but not initial CgA, identified patients with an unfavorable prognosis. A < 50% reduction of PSA 3 months after radiotherapy was associated with decreased failure-free 10 years urvival. Multivariate analysis demonstrated an increased risk of failure for patients with elevated pretreatment NSE and PSA values, T3 category, and decline of PSA less than 50% 3 months after radiotherapy. The presence of none or several risk factors (1-4) defined clearly separable groups.

CONCLUSIONS

Together with T category and pretreatment serum PSA values, serum NSE values before radiotherapy and decrease of serum PSA 3 months after radiotherapy represent easily assessable prognostic parameters in patients undergoing curative radiation treatment for prostate cancer.

Circulating neuroendocrine markers in patients with prostate carcinoma

BACKGROUND

Circulating neuroendocrine markers were measured in patients with prostate carcinoma (PC), prostatic intraepithelial neoplasia (PIN), and benign prostatic hypertrophy (BPH) with the goal to: 1) evaluate the differences in the expression of these markers in patients with benign, premalignant, and primary or metastatic PC; 2) evaluate their prognostic significance; 3) compare values in patients with hormone-naive and hormone-refractory disease; and 4) assess changes after androgen deprivation or chemotherapy.

METHODS

Serum neuron specific enolase (NSE) (immunoradiometric assay) and plasma chromogranin A (CgA) (enzyme-linked immunoadsorbent assay) were evaluated in 141 patients with BPH, 54 patients with PIN, and 159 patients with PC; 119 patients were bearing hormone-naive disease and 40 were bearing hormone-refractory disease. CgA was monitored in 31 patients submitted to androgen deprivation and in 24 patients receiving chemotherapy.

RESULTS

Supranormal CgA was observed more frequently in patients with American Urologic Association (AUA) Stage D2 disease (45.5%) compared with those with Stage D1 disease (33.3%), Stage C disease (16.7%), Stage A/B disease (18.8%), PIN (25.9%), and BPH (17.0%) (P < 0.02). Supranormal NSE did not change in any of the patient subgroups. Elevated CgA was observed in 36.0% of patients with metastases who had hormone-naive disease and in 45.0% of patients with hormone-refractory disease (P value not significant). Supranormal NSE and CgA values were predictors for poor prognosis in patients with hormone-refractory disease. Elevated baseline CgA values decreased > 50% in 1 of 12 patients who received luteinizing hormone-releasing hormone analogs and in 2 of 12 patients who underwent chemotherapy.

CONCLUSIONS

CgA appears to reflect the neuroendocrine activity of PC better than NSE. Elevated CgA values correlate with poor prognosis and are scarcely influenced by either endocrine therapy or chemotherapy.

Regressive changes and neuroendocrine differentiation in prostate cancer after neoadjuvant hormonal treatment

BACKGROUND

We studied the extent of neuroendocrine (NE) tumor cell differentiation and its relation to regressive changes in prostate cancer after 3-month hormonal treatment.

METHODS

Radical prostatectomy specimens from 103 patients, randomized to 3-month neoadjuvant LH-RH-analogue treatment (neoadjuvant group) or to surgery alone (control group), were available for analysis. The effects of hormonal treatment in terms of positive surgical margins, the degree of histopathological changes, and tumor cell proliferation were evaluated in relation to NE-differentiation assessed with antibodies against chromogranin A (CGA).

RESULTS

Both the number of CGA-positive cells/cm(2) (P < 0.003) and the proportion of NE-positive tumors (P = 0.07) were greater in the neoadjuvant group than in the control group. No correlation existed between NE-differentiation and the effects of the neoadjuvant hormonal treatment; nor did NE-differentiation correlate to the decrease in serum PSA.

CONCLUSIONS

Neuroendocrine differentiation in prostate cancer increases after 3 months of neoadjuvant hormonal treatment but does not correlate to the effects of hormonal treatment.

Effect of chromogranin A (pancreastatin) fragment on invasion of prostate cancer cells

We investigated the effect of chromogranin A (pancreastatin) fragment on the invasion of PC-3, DU-145 and LNCaP prostate cancer cells through a reconstituted basement membrane (Matrigel) using a Transwell cell culture chamber assay. Chromogranin A fragment increased the invasive capacity of both PC-3 and DU- 145 cells, whereas it had no significant effect of LNCaP cells. Chromogranin A fragment also increased the haptotactic migration of both PC-3 and DU-145 cells to fibronectin. Furthermore chromogranin A fragment increased the fibrinolytic activities of urokinase-type plasminogen activator (u-PA) in fibrin zymograms of both PC-3 and DU-145 cells and the expression of u-PA mRNA of PC-3 cells. However, the growth of these tumor cells was not affected by chromogranin A fragment at any concentrations used in this study. These results indicate that chromogranin A fragment increased the invasive potential of both PC-3 and DU-145 cells probably through enhancement of cell motility and the production of u-PA.

Neuroendocrine differentiation in prostatic carcinoma

BACKGROUND

Information is presented on prostatic neuroendocrine cells and neuroendocrine differentiation in prostatic carcinoma. The prognostic and therapeutic implications of neuroendocrine differentiation in prostatic carcinoma are reviewed.

METHODS

Data are presented that support the intriguing link between neuroendocrine differentiation, tumor progression, and androgen-independent prostate cancer. The hormones, and the receptors, expressed by prostatic neuroendocrine cells are investigated in order to elucidate their significance for prognosis and therapy.

RESULTS

The prognostic significance of neuroendocrine differentiation in prostatic malignancy has been controversial, but recent studies employing markers such as chromogranin A and neuron-specific enolase suggest that neuroendocrine differentiation, as reflected by increased tissue expression and/or blood levels of these neuroendocrine secretory products, correlates with poor prognosis, tumor progression, and androgen-independence. Since all malignant neuroendocrine cells are devoid of androgen receptors and since neuroendocrine phenotypic expression is not suppressed by androgen ablation, clonal propagation of androgen receptor-negative neuroendocrine cells may play an important role in the pathway towards the androgen-independent state of prostatic carcinoma. This would have significant implications for the treatment of prostate cancer, as several of the hormones known to be expressed by neuroendocrine-differentiated, malignant prostatic cells are potential candidates for drug therapy. A limited number of hormones have been tested in this context, in particular somatostatin, bombesin, and serotonin.

CONCLUSIONS

Neuroendocrine differentiation in carcinoma of the prostate appears to be associated with poor prognosis, tumor progression, and the androgen-independent state, for which there is currently no successful therapy. Therefore, new therapeutic protocols and trials need to be developed to test drugs based on neuroendocrine hormones and/or their antagonists. An evaluation of this new therapeutic approach against prostatic carcinoma with neuroendocrine differentiation, including hormone-refractory cancer, is easily justified, since these tumors are unresponsive to current modes of therapy.

Prostate-specific antigen and other markers of therapeutic response

Several new agents and combinations demonstrate significant activity in the treatment of patients with hormone refractory prostate cancer. Prostate-specific antigen (PSA) is being used increasingly as the key marker of a therapeutic response in trials of new agents. This article reviews data that support this marker as a surrogate endpoint, and it discusses the issues around the appropriateness of PSA as an intermediate marker with evolving noncytotoxic agents. Other biomarkers of prostate cancer progression are not uniformly elevated in men with advanced disease; to date, they are of limited clinical use. This article also discusses the rationale and results of novel and alternative biomarkers of prostate cancer progression.

Library of Sequence-specific Radioimmunoassays for Human Chromogranin A

Background: Human chromogranin A (CgA) is an acidic protein widely expressed in neuroendocrine tissue and tumors. The extensive tissue- and tumor-specific cleavages of CgA at basic cleavage sites produce multiple peptides.

Methods: We have developed a library of RIAs specific for different epitopes, including the NH2 and COOH termini and three sequences adjacent to dibasic sites in the remaining part of CgA.

Results: The antisera raised against CgA(210–222) and CgA(340–348) required a free NH2 terminus for binding. All antisera displayed high titers, high indexes of heterogeneity (∼1.0), and high binding affinities (Keff0 ∼ 0.1 × 1012 to 1.0 × 1012 L/mol), implying that the RIAs were monospecific and sensitive. The concentration of CgA in different tissues varied with the assay used. Hence, in a carcinoid tumor the concentration varied from 0.5 to 34.0 nmol/g tissue depending on the specificity of the CgA assay. The lowest concentration in all tumors was measured with the assay specific for the NH2 terminus of CgA. This is consistent with the relatively low concentrations measured in plasma from carcinoid tumor patients by the N-terminal assay, whereas the assays using antisera raised against CgA(210–222) and CgA(340–348) measured increased concentrations.

Conclusion: Only some CgA assays appear useful for diagnosis of neuroendocrine tumors, but the entire library is valuable for studies of the expression and processing of human CgA.

A new human chromogranin A (CgA) immunoradiometric assay involving monoclonal antibodies raised against the unprocessed central domain (145-245)

Chromogranin A (CgA), a major protein of chromaffin granules, has been described as a potential marker for neuroendocrine tumours. Because of an extensive proteolysis which leads to a large heterogeneity of circulating fragments, its presence in blood has been assessed in most cases either by competitive immunoassays or with polyclonal antibodies. In the present study, 24 monoclonal antibodies were raised against native or recombinant human CgA. Their mapping with proteolytic peptides showed that they defined eight distinct epitopic groups which spanned two-thirds of the C-terminal part of human CgA. All monoclonal antibodies were tested by pair and compared with a reference radioimmunoassay (RIA) involving CGS06, one of the monoclonal antibodies against the 198-245 sequence. It appears that CgA C-terminal end seems to be highly affected by proteolysis and the association of C-terminal and median-part monoclonal antibodies is inadequate for total CgA assessment. Our new immunoradiometric assay involves two monoclonal antibodies, whose contiguous epitopes lie within the median 145-245 sequence. This assay allows a sensitive detection of total human CgA and correlates well with RIA because dibasic cleavage sites present in the central domain do not seem to be affected by degradation. It has been proved to be efficient in measuring CgA levels in patients with neuroendocrine tumours.

Inability of bone turnover marker as a strong prognostic indicator in prostate cancer patients with bone metastasis: comparison with the extent of disease (EOD) grade

BACKGROUND

Although clinical investigations of bone turnover markers in prostate cancer patients have been conducted, the relationships of pretreatment levels of the markers to the prognosis of patients with bone metastasis has not been fully examined.

METHODS

The serum levels of carboxy-terminal propeptide of type I procollagen (PICP) and carboxy-terminal telopeptide of type I collagen (ICTP), alkaline phosphatase (ALP), and prostate-specific antigen (PSA) were examined in 48 untreated prostate cancer patients with bone metastasis, and the prognoses of the patients were evaluated using univariate and multivariate analyses.

RESULTS

The patients with low PICP or ALP values had significantly better outcomes in terms of cause-specific survival compared to the patients with high PICP or ALP values. There was no significant difference in survival between patients with high and low ICTP or PSA values. The multivariate analysis of PICP, ICTP, ALP, PSA, and extent of disease (EOD) grade revealed that only the EOD grade was an important prognostic indicator for survival.

CONCLUSIONS

These results demonstrate that the extent of bone metastasis evaluated by bone scintigrams is a more important prognostic indicator than are the serum biochemical markers of bone turnover.

Granin-A, parathyroid hormone-related protein, and calcitonin gene products in neuroendocrine prostate cancer

BACKGROUND

The importance of the expression of granin A (GRN-A, chromogranin-A), calcitonin (CT) gene products (CGPs), and parathyroid hormone-related protein (PTHrP) has become appreciated in the neuroendocrine (NE) differentiation of prostate cancer. We have studied the prostate expression of these three NE cell products with in vivo and in vitro methods.

METHODS

GRN-A secretion was measured by immunoassay in serum samples from patients with prostate cancer. Immunohistology procedures were used to assess GRN-A, CGPs, and PTHrP expression in paraffin-embedded prostate tissue samples. Serum and tumor findings were evaluated according to the patient's clinical status. All three substances were also studied in prostate cancer cell cultures.

RESULTS

GRN-A, PTHrP, and CGPs were all secreted products of prostate cancer. Our studies demonstrated that GRN-A can serve as a prostate cancer serum and tumor marker with clinical value for both diagnosis and prognosis. Elevated serum GRN-A levels identified patients with prostate cancer, including some who did not have elevated serum prostate-specific antigen (PSA) levels. Serum GRN-A concentrations also had prognostic value for prostate cancer. PTHrP and CGPs were expressed in prostate cancer in addition to GRN-A, and all three were secreted by prostate cells in culture. Each had effects on prostate cell growth.

CONCLUSIONS

GRN-A, PTHrP, and CGPs are produced and secreted by prostate cells. These three NE cell products can serve as tumor and markers for prostate cancer that have diagnostic and prognostic value. In addition, their derived peptides regulate prostate cell growth. However, studies more conclusive than the preliminary observations of our group and of other investigators are needed to define the roles of PTHrP, GRN-A, and CGPs in prostate cancer.

Chromogranin A: its clinical value as marker of neuroendocrine tumours

Chromogranin A (CgA) belongs to a family of secretory proteins that are present in densecore vesicles of neuroendocrine cells. Owing to its widespread distribution in neuroendocrine tissues, it can be used as an excellent immunohistochemical marker of neoplasms of neuroendocrine origin. It can also serve as serum marker of neuroendocrine activity because it is co-released with the peptide hormone content of the secretory granules. The serum concentration of CgA is elevated in patients with various neuroendocrine tumours. Elevated levels are strongly correlated with tumour volume. Although its sensitivity and specificity cannot compete with that of the specific hormonal secretion products of most of these tumours, it can nevertheless have useful clinical applications. Neuroendocrine tumours for which no peptide marker is available usually retain the capacity to secrete CgA. CgA can thus be used as serum marker for these so-called 'non-functioning' endocrine tumours. Moreover, in patients with carcinoids and phaeochromocytomas, CgA is a more stable and thus more easily manageable marker than plasma levels of respectively serotonin and catecholamines and their urinary metabolites. Its role as an important general neuroendocrine marker may be extended in the future by the development of immunoscintigraphy of membrane-bound CgA, allowing in vivo visualization of neuroendocrine neoplasms.

Granins and prostate cancer

OBJECTIVES

The importance of the expression of granin A (GRN-A, chromogranin-A) has become appreciated in the neuroendocrine differentiation of prostate cancer. We studied the expression of GRN-A in prostate cancer using serum immunoassay and tissue immunohistology procedures for this protein in order to define the clinical value of its measurements.

METHODS

GRN-A production was measured by immunoassay in serum samples from patients with prostate cancer. Immunohistology procedures were used to assess GRN-A expression in paraffin-embedded prostate tissue samples. Serum and tumor findings were evaluated according to the patient's clinical status in studies by us and others.

RESULTS

These studies demonstrated that GRN-A can serve as a prostate cancer serum and tumor marker with clinical value for both diagnosis and prognosis. Serum GRN-A was increased in early- and late-stage disease. Elevated serum GRN-A levels identified some patients with prostate cancer who did not have elevated serum prostate-specific antigen levels. In addition to their diagnostic value, increased serum GRN-A concentrations had prognostic value.

CONCLUSIONS

Our own studies as well as those of others support the clinical potential of GRN-A as a marker for early, progressive, and recurrent prostate cancer. This demonstration of clinical utility notwithstanding, further studies are needed to clearly define the clinical value of GRN-A as a serum and tumor marker for this common cancer.

Neuroendocrine differentiation in prostatic carcinoma during hormonal treatment

OBJECTIVES

Neuroendocrine differentiation (NED) is a common feature in adenocarcinoma of the prostate. Several studies suggest that NED may have a major impact on cancer progression as neuroendocrine (NE) secretory products have been shown to possess growth stimulatory effects. NED has also been proposed to constitute part of the mechanism by which a prostate cancer cell progresses toward androgen independence as NE tumor cells have been demonstrated to be devoid of androgen receptor immunoreactivity. In this retrospective study, we evaluated NED status in prostate cancer specimens from patients undergoing androgen ablation therapy.

METHODS

The degree of NED in transurethral resection of the prostate (TURP) samples from 53 patients with prostate cancer was investigated by immunocytochemistry using polyclonal rabbit immunoglobin G (IgG) against chromogranin A (CgA). Changes in NED with time were determined by a manual semiquantitative cell counting method.

RESULTS

During androgen withdrawal therapy, 21 tumors (40%) displayed increased NED concomitant with histopathologic tumor progression, whereas 29 carcinomas (55%) showed no change in NED status. However, a majority of the histopathologically unchanged tumors displayed marked NED at the first TURP and an increase in NED was by definition not possible. In only 3 cases (5%) was a decrease in NED observed with time.

CONCLUSIONS

Androgen ablation therapy may be a contributing factor to the increase in NED of prostatic adenocarcinoma with time, and our findings imply that androgen withdrawal therapy enhances the selection and progression of NED, androgen-independent tumor cells.