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As the primary screening test, E6/E7 mRNA has shown similar sensitivity for CIN3+ and lower positivity rate than the HPV DNA test. Nevertheless, the overall mRNA positivity is too high for immediate colposcopy, making a triage test necessary. The aim was to estimate the mRNA performance as a primary test with different triage strategies. All HPV DNA‐positives were tested for mRNA, cytology and p16/ki67. A sample of HPV DNA‐negatives was also tested for mRNA to estimate test specificity. We included all CIN3+ histologically diagnosed within 24 months since recruitment. Of the 41 127 participants, 7.7% were HPV DNA‐positive, of which 66.4% were mRNA‐positive. Among the HPV DNA‐negatives, 10/1108 (0.9%) were mRNA‐positive. Overall, 97 CIN3+ were found. If mRNA was used as the primary test, it would miss about 3% of all CIN3+ with a 22% reduction of positivity compared with HPV DNA. The weighted specificity estimate for

Abstract Background Invasive micropapillary carcinoma (IMPC) of the breast is a distinct and aggressive variant of luminal type B breast cancer that does not respond to neoadjuvant chemotherapy. It is characterized by small pseudopapillary clusters of cancer cells with inverted cell polarity. To investigate whether hypoxia-inducible factor-1 (HIF-1) activation may be related to the drug resistance described in this tumor, we used MCF7 cancer cells cultured as 3-D spheroids, which morphologically simulate IMPC cell clusters. Methods HIF-1 activation was measured by EMSA and ELISA in MCF7 3-D spheroids and MCF7 monolayers. Binding of HIF-1α to MDR-1 gene promoter and modulation of P-glycoprotein (Pgp) expression was evaluated by ChIP assay and FACS analysis, respectively. Intracellular doxorubicin retention was measured by spectrofluorimetric assay and drug cytotoxicity by annexin V-FITC measurement and caspase activity assay. Results In MCF7 3-D spheroids HIF-1 was activated and recruited to participate to the transcriptional activity of MDR-1 gene, coding for Pgp. In addition, Pgp expression on the surface of cells obtained from 3-D spheroids was increased. MCF7 3-D spheroids accumulate less doxorubicin and are less sensitive to its cytotoxic effects than MCF7 cells cultured as monolayer. Finally, HIF-1α inhibition either by incubating cells with 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (a widely used HIF-1α inhibitor) or by transfecting cells with specific siRNA for HIF-1α significantly decreased the expression of Pgp on the surface of cells and increased the intracellular doxorubicin accumulation in MCF7 3-D spheroids. Conclusions MCF7 breast cancer cells cultured as 3-D spheroids are resistant to doxorubicin and this resistance is associated with an increased Pgp expression in the plasma membrane via activation of HIF-1. The same mechanism may be suggested for IMPC drug resistance.

Background: The objective of this study was to describe the determinants of adequacy and positivity of the p16/Ki‐67 assay in a human papillomavirus (HPV)‐positive screening population enrolled within the New Technologies for Cervical Cancer 2 (NTCC2) study. Methods: ThinPrep slides were immunostained for p16/Ki‐67; each slide had 3 reports from different laboratories. The authors included population‐related, sampling‐related/staining‐related, and interpretation‐related variables in the analyses. Adequacy and positivity proportions were stratified by variables of interest. Univariate and multivariate logistic models were used to identify determinants of adequacy and positivity. Results: In total, 3100 consecutive HPV‐positive cases were analyzed. Because every slide was interpreted by 3 centers, 9300 reports were obtained, including 905 (9.7%) that were inadequate and 2632 (28.3%) that were positive. The percentage of cases in which all 3 reports were inadequate increased with increasing age of the women and with inadequate cytology. The highest percentage of adequacy in all 3 reports and of cases with all 3 reports positive was observed in specimens from women who had grade ≥2 cervical intraepithelial neoplasia (CIN2+), atypical squamous cells of undetermined significance or more severe (ASC‐US+) cytology, or mRNA positivity. The number of inadequate reports was significantly associated with increasing age, inadequate cytology, mRNA negativity, and scant cellularity. A positive p16/Ki‐67 report was associated with an ASC‐US+ result and with a positive mRNA result in cases both with and without CIN2+ but was associated with an HPV type 16 and/or 18 infection only in CIN2+ cases. The presence of CIN2+ was strongly associated with dual staining positivity. Conclusions: The interpretation of p16/Ki‐67 results may be influenced by several different variables, all of which are part of the steps in the procedure, and by the characteristics of the screened population. The determinants of adequacy and positivity of the p16/Ki‐67 assay are described in a human papillomavirus‐positive screening population. Even using the same assay and reporting the results according to the same criteria, the findings suggest that many variables linked to the characteristics of the population under study, the laboratory that performs the immunostaining, and/or the laboratory that interprets the slides should be taken into consideration. [ABSTRACT FROM AUTHOR]

Background: The study presents cross-sectional accuracy of E6 and E7 (E6/E7) mRNA detection and p16/ki67 dual staining, alone or in combination with cytology and human papillomavirus (HPV)16/18 genotyping, as a triage test in HPV DNA-positive women and their impact on cervical intraepithelial neoplasia (CIN2+) overdiagnosis.Methods: Women aged 25-64 years were recruited. HPV DNA-positive women were triaged with cytology and tested for E6/E7 mRNA and p16/ki67. Cytology positive women were referred to colposcopy, and negatives were randomly assigned to immediate colposcopy or to 1-year HPV retesting. Lesions found within 24 months since recruitment were included. All P values were 2-sided.Results: 40 509 women were recruited, and 3147 (7.8%) tested HPV DNA positive; 174 CIN2+ were found: sensitivity was 61.0% (95% confidence interval [CI] = 53.6 to 68.0), 94.4% (95% CI = 89.1 to 97.3), and 75.2% (95% CI = 68.1 to 81.6) for cytology, E6/E7 mRNA, and p16/ki67, respectively. Immediate referral was 25.6%, 66.8%, and 28.3%, respectively. Overall referral was 65.3%, 78.3%, and 63.3%, respectively. Cytology or p16/ki67, when combined with HPV16/18 typing, reached higher sensitivity with a small impact on referral. Among the 2306 HPV DNA-positive and cytology-negative women, relative CIN2+ detection in those randomly assigned at 1-year retesting vs immediate colposcopy suggests a -28% CIN2+ regression (95% CI = -57% to +20%); regression was higher in E6/E7 mRNA-negatives (Pinteraction = .29). HPV clearance at 1 year in E6/E7 mRNA and in p16/ki67 negative women was about 2 times higher than in positive women (Pinteraction < .001 for both).Conclusions: p16/ki67 showed good performance as a triage test. E6/E7 mRNA showed the highest sensitivity, at the price of too high a positivity rate to be efficient for triage. However, when negative, it showed a good prognostic value for clearance and CIN2+ regression. [ABSTRACT FROM AUTHOR]

BACKGROUND: p16/Ki-67 dual staining is a candidate biomarker for triaging human papillomavirus (HPV)--positive women. Reproducibility is needed for adopting a test for screening. This study assessed interlaboratory reproducibility in HPVpositive women. METHODS: All women positive for HPV from the Italian New Technologies for Cervical Cancer 2 study, were included in this study. ThinPrep slides were immunostained for p16/Ki-67 in 4 laboratories and were interpreted in 7 laboratories. Each slide had 3 reports from different laboratories. Slides were classified as valuable or inadequate, and valuable slides were classified as positive (at least 1 double-stained cell) or negative. Interlaboratory reproducibility was evaluated with κ values. RESULTS: Overall, we obtained 9300 reports for 3100 cases; 905 reports (9.7%) were inadequate. The overall adequacy concordance was poor (κ = 0.224; 95% confidence interval [CI], 0.183-0.263). The overall positivity concordance was moderate (κ = 0.583; 95% CI, 0.556-0.610). Of the 176 cervical intraepithelial neoplasia 2+ (CIN-2+) lesions found in HPV DNA-- positive women, 158 had a valid result: 107 were positive in all 3 reports (sensitivity for CIN-2+, 67.7%; 95% CI, 59.8%-74.9%), 23 were positive in 2 reports (sensitivity of the majority report, 82.3%; 95% CI, 75.4%-87.9%), and 15 were positive in 1 report (sensitivity of at least 1 positive result, 91.8%; 95% CI, 86.3%-95.5%). Thirteen CIN-2+ cases were negative in all 3 reports. The overall positivity concordance in CIN-2+ samples was κ = 0.487 (95% CI, 0.429-0.534), whereas in the non--CIN-2+ samples, it was κ = 0.558 (95% CI, 0.528-0.588). CONCLUSIONS: The p16/Ki-67 assay showed poor reproducibility for adequacy and good reproducibility for positivity comparable to that of cervical cytology. Nevertheless, the low reproducibility does not affect the sensitivity for CIN-2+. [ABSTRACT FROM AUTHOR]

Background: The accumulation of cyclin-dependent kinase inhibitor 2A (p16ink4a ) protein in a cell is associated with neoplastic progression in precancerous cervical lesions. Dual staining for p16ink4a and Ki-67 has been proposed as a triage test in cervical cancer screening for women who test positive for human papillomavirus DNA. In this study, interobserver reproducibility of the interpretation of this test was assessed.Methods: Forty-two immunostained, liquid-based cytology slides were divided into 2 sets and were interpreted by 17 to 21 readers from 9 different laboratories, yielding a total of 816 reports. Immunostaining results were classified as positive, negative, inconclusive, or inadequate. After evaluation of the first set of slides and before circulation of the second set, the results were discussed in a plenary meeting. The 10 slides with the most discordant results were evaluated again by selected expert cytopathologists.Results: The overall κ value was 0.612 (95% confidence interval [CI], 0.523-0.701), it was higher for the positive and negative categories (κ = 0.692 and κ = 0.641, respectively), and it was almost null for the inconclusive category (κ = 0.058). Considering only readers from laboratories with documented experience, the κ value was higher (κ = 0.747; 95% CI, 0.643-0.839) compared with nonexperienced centers (κ = 0.498; 95% CI, 0.388-0.616). The results were similar in both sets of slides (κ = 0.505 [95% CI, 0.358-0.642] and κ = 0.521 [95% CI, 0.240-0.698] for the first and second sets, respectively). Reinterpretation of the slides with the most discordant results did not provide any improvement (first evaluation, κ = 0.616 [95% CI, 0.384-0.866]; second evaluation, κ = 0.403 [95% CI, 0.182-0.643]).Conclusions: Dual staining for p16 ink4a and Ki-67 demonstrated good reproducibility, confirming its robustness, which is a necessary prerequisite for its adoption as a triage test in cervical cancer screening programs that use human papillomavirus DNA as a primary test. Cancer Cytopathol 2017;125:212-220. © 2016 American Cancer Society. [ABSTRACT FROM AUTHOR]

BACKGROUND The triage of human papillomavirus (HPV)-positive women is needed to avoid overreferral to colposcopy. p16INK4a immunostaining is an efficient triage method. p16INK4a/Ki-67 dual staining was introduced mainly to increase reproducibility and specificity compared with stand-alone p16INK4a staining. METHODS Within a pilot project, HPV-positive women were referred to colposcopy if cytology was abnormal or unsatisfactory or HPV testing was still positive after 1 year. For 500 consecutive women, a slide obtained during colposcopy was immunostained for p16INK4a/Ki-67 and independently interpreted by 7 readers without previous experience with dual staining. Four of these readers were experts in cervical pathology and 3 were not. Kappa values for multiple raters, sensitivity, and specificity for cervical intraepithelial neoplasia type 2-positive histology were computed. Because women with normal cytology were underrepresented, estimates for all HPV-positive women were obtained as weighted means of cytology-specific estimates. RESULTS The overall kappa for HPV-positive women was 0.70 (95% confidence interval [95% CI], 0.60-0.77). Kappa values were not found to be significantly different between expert and nonexpert readers with regard to cervical cytology but were significantly increased ( P =. 0066) after consensus discussion. The overall specificity estimate for HPV-positive women was 64.0% (95% CI, 57.4%-70.2%): 66.7% (95% CI, 59.8%-73.0%) for experts and 60.5% (95% CI, 59.8%-73.0%) for nonexperts. Among women with abnormal cytology, the sensitivity was 85.5% (95% CI, 77.9%-90.8%): 85.8% (95% CI, 77.9%-91.2%) for experts and 85.1% (95% CI, 76.6%-90.9%) for nonexperts. CONCLUSIONS p16INK4a/Ki-67 immunostaining demonstrated good reproducibility and specificity when triaging HPV-positive women. Dual-staining interpretation can be performed, after short training, even by staff who are not experts in cervical cytology. This allows HPV-based screening with triage to be performed in settings in which such expert staff is not available. Cancer (Cancer Cytopathol) 2015;123:212-218. © 2014 American Cancer Society. [ABSTRACT FROM AUTHOR]

Background: Invasive micropapillary carcinoma (IMPC) of the breast is a distinct and aggressive variant of luminal type B breast cancer that does not respond to neoadjuvant chemotherapy. It is characterized by small pseudopapillary clusters of cancer cells with inverted cell polarity. To investigate whether hypoxia-inducible factor-1 (HIF-1) activation may be related to the drug resistance described in this tumor, we used MCF7 cancer cells cultured as 3-D spheroids, which morphologically simulate IMPC cell clusters. Methods: HIF-1 activation was measured by EMSA and ELISA in MCF7 3-D spheroids and MCF7 monolayers. Binding of HIF-1α to MDR-1 gene promoter and modulation of P-glycoprotein (Pgp) expression was evaluated by ChIP assay and FACS analysis, respectively. Intracellular doxorubicin retention was measured by spectrofluorimetric assay and drug cytotoxicity by annexin V-FITC measurement and caspase activity assay. Results: In MCF7 3-D spheroids HIF-1 was activated and recruited to participate to the transcriptional activity of MDR-1 gene, coding for Pgp. In addition, Pgp expression on the surface of cells obtained from 3-D spheroids was increased. MCF7 3-D spheroids accumulate less doxorubicin and are less sensitive to its cytotoxic effects than MCF7 cells cultured as monolayer. Finally, HIF-1α inhibition either by incubating cells with 3-(5'-hydroxymethyl-2'- furyl)-1-benzylindazole (a widely used HIF-1α inhibitor) or by transfecting cells with specific siRNA for HIF-1α significantly decreased the expression of Pgp on the surface of cells and increased the intracellular doxorubicin accumulation in MCF7 3-D spheroids. Conclusions: MCF7 breast cancer cells cultured as 3-D spheroids are resistant to doxorubicin and this resistance is associated with an increased Pgp expression in the plasma membrane via activation of HIF-1. The same mechanism may be suggested for IMPC drug resistance. [ABSTRACT FROM AUTHOR]

The purpose of this article is to evaluate the prognostic value of androgen receptor (AR) expression in patients with estrogen receptor (ER)-positive breast cancer, treated with endocrine therapy, with or without the addition of chemotherapy. A consecutive series of 953 patients with ER-positive breast cancer, treated between 1998 and 2003, was selected. Repeated immunohistochemistry confirmed the expression of ER in the tumor of 938 patients. AR expression was measured by immunohistochemistry. The Kaplan-Meier method, logrank test and multivariate Cox models were used to explore the impact of AR expression on time to relapse (TTR) and disease specific survival (DSS) in all patients and in subgroups treated with chemo-endocrine therapy or endocrine therapy alone. AR immunoreactivity was assessable in 859 tumors and positive in 609 (70.9%). AR expression was a significant marker of good prognosis for TTR ( P = 0.001) and DSS ( P < 0.001). This effect was particularly evident in the group of patients receiving chemo-endocrine therapy (TTR ( P = 0.015) and DSS ( P < 0.001)). Cox models confirmed AR as an independent variable for both TTR ( P = 0.003, HR 0.444, 95%CI 0.258-0.765) and DSS ( P < 0.001, HR 0.135, 95%CI 0.054-0.337). Thus, we focused on ER-positive luminal B breast cancer that may be selected for chemotherapy because of their more aggressive immunophenotype. In this subset AR expression identified a group of patients with better prognosis for TTR ( P = 0.017, HR 0.521, 95%CI 0.306-0.888) and DSS ( P = 0.001, HR 0.276, 95% CI 0.130-0.588). AR expression is an independent prognostic factor of better outcome in patients with ER-positive breast cancers. [ABSTRACT FROM AUTHOR]

The use of clinically validated human papillomavirus (HPV) assays is recommended in cervical cancer screening, and extended genotyping is getting attention as a triage biomarker because of the different oncogenic risk of the high-risk HPV genotypes. We compared the results of the Becton & Dickinson (BD) Onclarity HPV assay, on the residual baseline cervico-vaginal specimens of the NTCC2 trial, to those of the screening HPV-DNA assay (Cobas 4800 or HC2) and to cytology, p16/ki67 and E6/E7 mRNA triage results. We genotyped virtually all HPV-positive women and a consecutive sample of HPV-negatives. Among the 3,129 baseline-positives, 75.5% ( k = 0.368) were BD-positive, as were 5 of the 333 baseline-negatives (1.5%). The concordance between BD and HPV-DNA screening test was 87% for Cobas (1,250/1,436) and 65.9% for HC2 (1,115/1,693). A higher than the recommended positivity threshold for Onclarity would increase the agreement but would not improve concordance in the overall screening population. Among the baseline-positive cases, we observed an increasing trend of BD positivity with cytology severity (from 71.6% in negative for intraepithelial lesion of malignancy to 95.1% in ASC-H+ samples), with histologically confirmed CIN3 (96.9%), with p16/ki67 dual staining positivity (90.9% among the positive and 69.6% among the negative specimens), and with E6/E7 mRNA positivity (93.4% in the mRNA-positive cases vs 39.7% among the mRNA-negatives). Our findings confirm some disagreement among different HPV assays used for screening. Nevertheless, the agreement is substantial for women with high-grade cytology, histologically confirmed CIN3, and p16/ki67 or mRNA positivity at triage, thus confirming a good clinical performance of all the tests used.The NTCC2 trial is registered as Clinicaltrials.gov identifier NCT01837693., Importance: Large randomized clinical trials have demonstrated that human papillomavirus (HPV) testing for high-risk types is more effective than cytology in detecting pre-cancerous lesions and preventing cervical cancer. Its use is being implemented in cervical cancer screening in several countries. The most recent guidelines recommend a risk-based management. It is therefore important to assess the individual risk of having/developing high-grade lesions of women testing high-risk HPV-positive. A crucial viral factor influencing the risk is the HPV genotype since different types are associated to different carcinogenetic risks. Understanding the degree of concordance among different assays targeting either HPV presence/type(s) or cellular morphology and proteins' expression provides knowledge useful to better define how these tests can be used in screening protocols for an effective triage and to anticipate the possible implementation issues. Our study shows that the concordance between tests is higher when the infections have a higher probability of producing a clinically relevant lesion., Competing Interests: M.B. and P.G.R., as principal investigator and former PI of the NTCC2 study, report nonfinancial support from Roche Diagnostics and Hologic S.r.l., which provided part of the reagents for free or at reduced price. Moreover, M.B., P.G.R., S.B., and L.D.M. obtained financial and nonfinancial support from Becton & Dickinson. M.B. also reports financial and nonfinancial support from Arrow S.r.l. for works outside this project. All other authors declare no conflict of interest.

Background: The accumulation of cyclin-dependent kinase inhibitor 2A (p16 ink4a ) protein in a cell is associated with neoplastic progression in precancerous cervical lesions. Dual staining for p16 ink4a and Ki-67 has been proposed as a triage test in cervical cancer screening for women who test positive for human papillomavirus DNA. In this study, interobserver reproducibility of the interpretation of this test was assessed., Methods: Forty-two immunostained, liquid-based cytology slides were divided into 2 sets and were interpreted by 17 to 21 readers from 9 different laboratories, yielding a total of 816 reports. Immunostaining results were classified as positive, negative, inconclusive, or inadequate. After evaluation of the first set of slides and before circulation of the second set, the results were discussed in a plenary meeting. The 10 slides with the most discordant results were evaluated again by selected expert cytopathologists., Results: The overall κ value was 0.612 (95% confidence interval [CI], 0.523-0.701), it was higher for the positive and negative categories (κ = 0.692 and κ = 0.641, respectively), and it was almost null for the inconclusive category (κ = 0.058). Considering only readers from laboratories with documented experience, the κ value was higher (κ = 0.747; 95% CI, 0.643-0.839) compared with nonexperienced centers (κ = 0.498; 95% CI, 0.388-0.616). The results were similar in both sets of slides (κ = 0.505 [95% CI, 0.358-0.642] and κ = 0.521 [95% CI, 0.240-0.698] for the first and second sets, respectively). Reinterpretation of the slides with the most discordant results did not provide any improvement (first evaluation, κ = 0.616 [95% CI, 0.384-0.866]; second evaluation, κ = 0.403 [95% CI, 0.182-0.643])., Conclusions: Dual staining for p16 ink4a and Ki-67 demonstrated good reproducibility, confirming its robustness, which is a necessary prerequisite for its adoption as a triage test in cervical cancer screening programs that use human papillomavirus DNA as a primary test. Cancer Cytopathol 2017;125:212-220. © 2016 American Cancer Society., (© 2016 American Cancer Society.)

Background: The triage of human papillomavirus (HPV)-positive women is needed to avoid overreferral to colposcopy. p16(INK4a) immunostaining is an efficient triage method. p16(INK4a) /Ki-67 dual staining was introduced mainly to increase reproducibility and specificity compared with stand-alone p16(INK4a) staining., Methods: Within a pilot project, HPV-positive women were referred to colposcopy if cytology was abnormal or unsatisfactory or HPV testing was still positive after 1 year. For 500 consecutive women, a slide obtained during colposcopy was immunostained for p16(INK4a) /Ki-67 and independently interpreted by 7 readers without previous experience with dual staining. Four of these readers were experts in cervical pathology and 3 were not. Kappa values for multiple raters, sensitivity, and specificity for cervical intraepithelial neoplasia type 2-positive histology were computed. Because women with normal cytology were underrepresented, estimates for all HPV-positive women were obtained as weighted means of cytology-specific estimates., Results: The overall kappa for HPV-positive women was 0.70 (95% confidence interval [95% CI], 0.60-0.77). Kappa values were not found to be significantly different between expert and nonexpert readers with regard to cervical cytology but were significantly increased (P =. 0066) after consensus discussion. The overall specificity estimate for HPV-positive women was 64.0% (95% CI, 57.4%-70.2%): 66.7% (95% CI, 59.8%-73.0%) for experts and 60.5% (95% CI, 59.8%-73.0%) for nonexperts. Among women with abnormal cytology, the sensitivity was 85.5% (95% CI, 77.9%-90.8%): 85.8% (95% CI, 77.9%-91.2%) for experts and 85.1% (95% CI, 76.6%-90.9%) for nonexperts., Conclusions: p16(INK4a) /Ki-67 immunostaining demonstrated good reproducibility and specificity when triaging HPV-positive women. Dual-staining interpretation can be performed, after short training, even by staff who are not experts in cervical cytology. This allows HPV-based screening with triage to be performed in settings in which such expert staff is not available., (© 2014 American Cancer Society.)

Data on the presence of oxytocin receptors (OTR) within the prostate are still controversial and variable among different species. In the present study, OTR expression and localization has been investigated in human hyperplastic and neoplastic prostate at mRNA and protein levels using in situ hybridization (ISH) and immunohistochemistry (ICC) techniques, respectively. In all the cases studied, epithelial cells expressed OTR mRNA and protein. Interestingly, this expression was more intense in neoplastic epithelial cells compared to the hyperplastic ones. In order to determine whether OTR might mediate a biological effect of oxytocin (OT) in prostate cancer cells, OTR expression was studied by RT-PCR and immunofluorescence technique in the human androgen-independent prostate cancer cell line DU145. In addition, a possible heterotopic production of OT by DU145 cells was studied using RT-PCR. The data obtained showed that DU145 cells expressed OTR, whereas no OT mRNA was detected. When DU145 cells were treated with OT (100 nM) a significant inhibition of cell proliferation was observed, while co-incubation with the OT antagonist OTA (100 nm) abolished such an effect. The involvement of apoptosis in the OT effect contrasting cell proliferation was excluded by ISEL technique, which revealed a similar pattern of DNA fragmentation in either untreated or OT-treated cells. Altogether, the data indicate that the OT/OTR system could be involved in the control of prostate neoplastic pathology.

Background: Ghrelin, a natural growth hormone secretagogue (GHS), has been identified in prostate carcinoma cell lines., Objectives: To investigate the presence of ghrelin and its receptors in human prostate tumours and in DU-145, PC-3 and LNCaP prostate carcinoma cell lines, and to assess the effects of ghrelin and its more abundant circulating form, des-octanoyl ghrelin, on cell proliferation., Methods: Ghrelin and types 1a and 1b GHS receptor (GHS-R) were determined at the mRNA and protein levels by RT-PCR, in situ hybridization, immunohistochemistry and enzyme immunoassay in tissues, cell lines and culture medium. Ghrelin binding was determined by radioreceptor assay. The effects on cell proliferation were evaluated by growth curves., Results: Ghrelin mRNA was found in prostatic carcinomas and benign hyperplasias, but immunohistochemistry was negative. GHS-R1a and 1b mRNAs were absent from carcinomas, but GHS-R1b mRNA was present in 50% of hyperplasias. Ghrelin peptide and mRNA were present in PC-3 cells exclusively, whereas GHS-R1a and 1b mRNAs were expressed in DU-145 cells only. Specific [125I]Tyr4-ghrelin binding was detected in prostate tumour, DU-145 and PC-3 cell membranes and the binding was displaced by ghrelin, synthetic GHS and des-octanoyl ghrelin, which is devoid of GHS-R1a binding affinity and GH-releasing activity. Ghrelin and des-acyl ghrelin inhibited DU-145 cell proliferation, displayed a biphasic effect in PC-3 cells and were ineffective in LNCaP cells., Conclusions: Specific GHS binding sites, other than GHS-R1a and 1b, are present in human prostatic neoplasms. Ghrelin, in addition to des-acyl ghrelin, exerts different effects on cell proliferation in prostate carcinoma cell lines.