- Email: [email protected]
Serum dipeptidyl peptidase IV activity and sCD26 concentration in patients with choroidal nevus or uveal melanoma
Clinica Chimica Acta 448 (2015) 193–194
Contents lists available at ScienceDirect
Clinica Chimica Acta journal homepage: www.elsevier.com/locate/clinchim
Letter to the editor Serum dipeptidyl peptidase IV activity and sCD26 concentration in patients with choroidal nevus or uveal melanoma
Keywords: Soluble CD26 (sCD26) Dipeptidyl peptidase activity (DPP-IV) Biomarker Diagnosis Choroidal nevus Uveal melanoma
Dear Editor, Uveal malignant melanoma (UM) is the most frequent primary intraocular tumor in adult humans [1]. There is substantial evidence that intraocular melanomas including metastatic disease arise from benign nevi in the uveal tract. Even when the primary tumor in the eye is diagnosed and treated, metastasis can develop in up 50% of patients after a long disease-free interval suggesting the presence of metastatic stem cells [2]. Metastasis is established preferentially in the liver, being this fact the leading cause of death in UM (90% of the individuals). There is no laboratory biomarker of clinical use contributing to the detection of UM at the earliest stages and/or to improve prognosis of UM metastatic potential [3,4]. Serum levels of soluble CD26 (sCD26) and its dipeptidyl peptidase activity (DPP-IV) have been proposed as biomarkers for lung and colorectal cancer screening including metastasis detection [5–9]. A pilot study was designed to check their potential for ocular cancer detection. ELISA, immunoblotting and a kinetic method [6,7,10] were applied to determine the serum levels and enzyme activity in patients of choroidal nevus (n = 29), UM (n = 7) and UM starting therapy (n = 20), compared to healthy donors (external, n = 25, and Service attendees, n = 22). Tumor characteristics such as tumor location, tumor size or therapy modality (plaque versus enucleation) were recorded. Both DPP-IV activity and sCD26 concentration were higher in UM but statistically significant only the former (p = 0.001; one-way ANOVA). While both variables were not related with the tumor location or therapy modality (when corresponded), DPP-IV activity levels correlated with tumor size in the group of melanoma patients undergoing therapy (r = 0.561, p = 0.015; Pearson's correlation coefficient, with tumor height) or in UM patients as a whole (data not shown) highlighting the pathophysiological meaning of its raising.
Abbreviations: (UM), uveal melanoma; (DPP-IV), dipeptidyl peptidase activity; (CRC), colorectal cancer; (CSCs), cancer stem cells.
http://dx.doi.org/10.1016/j.cca.2015.07.007 0009-8981/© 2015 Published by Elsevier B.V.
Diagnostic efficiency of serum sCD26 and DPP-IV levels was tested after finding that UM groups showed “anomalous” values only above a high cut-off provisionally constructed in the same way that sCD26 cut-offs [6–8]. A cut-off for specificity values close to 90%, as typically required in a screening setting, was selected by the ROC (data not shown). With a cut-off of 54 IU L−1, there were statistically significant differences between groups according to the frequency of “anomalous” values (two-tailed Fisher's Exact test), especially between nevus and UM patients undergoing therapy when compared against both control groups (Fig. 1). Specificity data calculated from this cut-off were 80% and 86% for the healthy donors or the service control group respectively (5 out 25 healthy control, and 3 out 22 service control cases were false positives), and sensitivity data were 31% for choroidal nevus (9 out 29) and 59% for UM (16 out 27 were true positives considering all UM cases, 65% considering the group with therapy alone), data of enough quality to maintain this cut-off until new studies with larger cohorts. This diagnostic data were found in spite of disturbing demographic data with age: while in the two groups of younger subjects (b35 years and 36–55 years) the patients showed elevated levels of both
Fig. 1. Cut off values for serum sCD26 and DPP-IV and frequency of anomalous values in UM patients and healthy donors. DPP-IV enzyme activity for healthy donors (HD), Ophthalmology Service control patients (Serv. ctrl), patients with nevus (Nevus), patients with UM undergoing treatment (UM-treated) and patients with UM (UM) are shown. Line represents cut-off value of 54 IU L−1 obtained as described in the main text. Significant differences in the number of out-of-range values were found between nevus and UM-treated patients when compared against both control groups.
194
Letter to the editor
biomarkers, particularly of DPP-IV activity, this was not seen in the older group (N 55). We studied possible correlations between both biomarkers among the different groups of patients. As expected, in healthy donors both parameters correlate significantly (r = 0.436, p = 0.029), a correlation that it is lost in the control group of patients without nevus or UM recruited in the Ophthalmology Service (r = 0.356, p = 0.104) indicating that other pathologies are affecting this correlation. When all patients were considered as a unique population a similar correlation between DPP-IV and sCD26 was observed (r = 0.487, p b 0.001). When each patient group was analyzed individually a strong correlation is observed for nevus patients (r = 0.723, p b 0.001) and non-treated UM patients (r = 0.828, p = 0.022), but interestingly it is lost in those patients with UM under therapy (r = 0.126, p = 0.595). These data indicate that DPP-IV/sCD26 is disturbed in UM. In addition, the subset of nevus patients that showed elevated levels of both biomarkers is different to the subset of nevus patients with high risk to evolve to UM (data not shown). Our previous reports indicated the potential usefulness of sCD26 as a biomarker for colorectal cancer, particularly in early diagnosis [5–7] and follow-up [8]. In the latter case, increased levels could be valuable for the early detection of local and distant recurrence [8], perhaps related to the presence of CD26-expressing CSCs [8,9]. Further biochemical research is then needed. However, it is plausible that determination of both serum biomarkers in follow-up studies of these diseases might contribute to earlier UM diagnosis and, perhaps, prognosis of metastasis. Acknowledgments We thank CTG (Centro de Transfusión de Galicia) for their help with the blood samples from the healthy donors. This research was partially supported by Consellería de Educación e Ordenación Universitaria da Xunta de Galicia (CN 2011/024), and Agrupación Estratégica INBIOMED (Investigación en Biomedicina) (CN 2012/273), from DXPCTSUG (Dirección Xeral de Promoción Científica e Tecnolóxica do Sistema Universitario de Galicia) and FEDER (Fondo Europeo de Desarrollo Regional) EU funding. References [1] A.D. Singh, M.E. Turell, A.K. Topham, Uveal melanoma: trends in incidence, treatment, and survival, Ophthalmology 118 (2011) 1881–1885. [2] B. Damato, Does ocular treatment of uveal melanoma influence survival? Br. J. Cancer 103 (2010) 285–290. [3] T. Sato, Locoregional management of hepatic metastasis from primary uveal melanoma, Semin. Oncol. 37 (2010) 127–138.
[4] V. Torres, P. Triozzi, C. Eng, R. Tubbs, L. Schoenfiled, J.W. Crabb, et al., Circulating tumor cells in uveal melanoma, Future Oncol. 7 (2011) 101–109. [5] O.J. Cordero, F.J. Salgado, M. Nogueira, On the origin of serum CD26 and its altered concentration in cancer patients, Cancer Immunol. Immunother. 58 (2009) 1723–1747. [6] L. De Chiara, A.M. Rodríguez-Piñeiro, F.J. Rodríguez-Berrocal, O.J. Cordero, D. Martínez-Ares, M. Páez de la Cadena, Serum CD26 is related to histopathological polyp traits and behaves as a marker for colorectal cancer and advanced adenomas, BMC Cancer 10 (2010) 333. [7] O.J. Cordero, D. Ayude, M. Nogueira, F.J. Rodriguez-Berrocal, M.P. de la Cadena, Preoperative serum CD26 levels: diagnostic efficiency and predictive value for colorectal cancer, Br. J. Cancer 83 (2000) 1139–1146. [8] L. De Chiara, A.M. Rodríguez-Piñeiro, O.J. Cordero, L. Vázquez-Tuñas, D. Ayude, F.J. Rodríguez-Berrocal, M.P. de la Cadena, Postoperative serum levels of sCD26 for surveillance in colorectal cancer patients, PLoS One 9 (2014) e107470. [9] R. Pang, W.L. Law, A.C. Chu, J.T. Poon, C.S. Lam, A.K. Chow, L. Ng, L.W. Cheung, X.R. Lan, H.Y. Lan, V.P. Tan, T.C. Yau, R.T. Poon, B.C. Wong, A subpopulation of CD26+ cancer stem cells with metastatic capacity in human colorectal cancer, Cell Stem Cell 6 (2010) 603–615. [10] A.M. Lambeir, C. Durinx, S. Scharpé, I. De Meester, Dipeptidyl-peptidase IV from bench to bedside: an update on structural properties, functions, and clinical aspects of the enzyme DPP IV, Crit. Rev. Clin. Lab. Sci. 40 (2003) 209–294.
Rubén Varela-Calviño Mónica Imbernón1 Department of Biochemistry and Molecular Biology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain Lorena Vázquez-Iglesias María Páez de la Cadena Department of Biochemistry, Genetics and Immunology, University of Vigo, 36200 Vigo, Spain Manuel Bande-Rodríguez Antonio Piñeiro Service of Ophtalmology, University Hospital Complex of Santiago de Compostela, SERGAS, Santiago de Compostela, Spain María Pardo Obesidomics Group, IDIS (Health Research Institute of Santiago de Compostela), SERGAS, Santiago de Compostela, Spain Oscar J. Cordero⁎ Department of Biochemistry and Molecular Biology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain Corresponding author. E-mail address: [email protected]. 6 July 2015 Available online 9 July 2015
1 Present address: Department of Physiology, University of Santiago de Compostela, Spain.
Contents lists available at ScienceDirect
Clinica Chimica Acta journal homepage: www.elsevier.com/locate/clinchim
Letter to the editor Serum dipeptidyl peptidase IV activity and sCD26 concentration in patients with choroidal nevus or uveal melanoma
Keywords: Soluble CD26 (sCD26) Dipeptidyl peptidase activity (DPP-IV) Biomarker Diagnosis Choroidal nevus Uveal melanoma
Dear Editor, Uveal malignant melanoma (UM) is the most frequent primary intraocular tumor in adult humans [1]. There is substantial evidence that intraocular melanomas including metastatic disease arise from benign nevi in the uveal tract. Even when the primary tumor in the eye is diagnosed and treated, metastasis can develop in up 50% of patients after a long disease-free interval suggesting the presence of metastatic stem cells [2]. Metastasis is established preferentially in the liver, being this fact the leading cause of death in UM (90% of the individuals). There is no laboratory biomarker of clinical use contributing to the detection of UM at the earliest stages and/or to improve prognosis of UM metastatic potential [3,4]. Serum levels of soluble CD26 (sCD26) and its dipeptidyl peptidase activity (DPP-IV) have been proposed as biomarkers for lung and colorectal cancer screening including metastasis detection [5–9]. A pilot study was designed to check their potential for ocular cancer detection. ELISA, immunoblotting and a kinetic method [6,7,10] were applied to determine the serum levels and enzyme activity in patients of choroidal nevus (n = 29), UM (n = 7) and UM starting therapy (n = 20), compared to healthy donors (external, n = 25, and Service attendees, n = 22). Tumor characteristics such as tumor location, tumor size or therapy modality (plaque versus enucleation) were recorded. Both DPP-IV activity and sCD26 concentration were higher in UM but statistically significant only the former (p = 0.001; one-way ANOVA). While both variables were not related with the tumor location or therapy modality (when corresponded), DPP-IV activity levels correlated with tumor size in the group of melanoma patients undergoing therapy (r = 0.561, p = 0.015; Pearson's correlation coefficient, with tumor height) or in UM patients as a whole (data not shown) highlighting the pathophysiological meaning of its raising.
Abbreviations: (UM), uveal melanoma; (DPP-IV), dipeptidyl peptidase activity; (CRC), colorectal cancer; (CSCs), cancer stem cells.
http://dx.doi.org/10.1016/j.cca.2015.07.007 0009-8981/© 2015 Published by Elsevier B.V.
Diagnostic efficiency of serum sCD26 and DPP-IV levels was tested after finding that UM groups showed “anomalous” values only above a high cut-off provisionally constructed in the same way that sCD26 cut-offs [6–8]. A cut-off for specificity values close to 90%, as typically required in a screening setting, was selected by the ROC (data not shown). With a cut-off of 54 IU L−1, there were statistically significant differences between groups according to the frequency of “anomalous” values (two-tailed Fisher's Exact test), especially between nevus and UM patients undergoing therapy when compared against both control groups (Fig. 1). Specificity data calculated from this cut-off were 80% and 86% for the healthy donors or the service control group respectively (5 out 25 healthy control, and 3 out 22 service control cases were false positives), and sensitivity data were 31% for choroidal nevus (9 out 29) and 59% for UM (16 out 27 were true positives considering all UM cases, 65% considering the group with therapy alone), data of enough quality to maintain this cut-off until new studies with larger cohorts. This diagnostic data were found in spite of disturbing demographic data with age: while in the two groups of younger subjects (b35 years and 36–55 years) the patients showed elevated levels of both
Fig. 1. Cut off values for serum sCD26 and DPP-IV and frequency of anomalous values in UM patients and healthy donors. DPP-IV enzyme activity for healthy donors (HD), Ophthalmology Service control patients (Serv. ctrl), patients with nevus (Nevus), patients with UM undergoing treatment (UM-treated) and patients with UM (UM) are shown. Line represents cut-off value of 54 IU L−1 obtained as described in the main text. Significant differences in the number of out-of-range values were found between nevus and UM-treated patients when compared against both control groups.
194
Letter to the editor
biomarkers, particularly of DPP-IV activity, this was not seen in the older group (N 55). We studied possible correlations between both biomarkers among the different groups of patients. As expected, in healthy donors both parameters correlate significantly (r = 0.436, p = 0.029), a correlation that it is lost in the control group of patients without nevus or UM recruited in the Ophthalmology Service (r = 0.356, p = 0.104) indicating that other pathologies are affecting this correlation. When all patients were considered as a unique population a similar correlation between DPP-IV and sCD26 was observed (r = 0.487, p b 0.001). When each patient group was analyzed individually a strong correlation is observed for nevus patients (r = 0.723, p b 0.001) and non-treated UM patients (r = 0.828, p = 0.022), but interestingly it is lost in those patients with UM under therapy (r = 0.126, p = 0.595). These data indicate that DPP-IV/sCD26 is disturbed in UM. In addition, the subset of nevus patients that showed elevated levels of both biomarkers is different to the subset of nevus patients with high risk to evolve to UM (data not shown). Our previous reports indicated the potential usefulness of sCD26 as a biomarker for colorectal cancer, particularly in early diagnosis [5–7] and follow-up [8]. In the latter case, increased levels could be valuable for the early detection of local and distant recurrence [8], perhaps related to the presence of CD26-expressing CSCs [8,9]. Further biochemical research is then needed. However, it is plausible that determination of both serum biomarkers in follow-up studies of these diseases might contribute to earlier UM diagnosis and, perhaps, prognosis of metastasis. Acknowledgments We thank CTG (Centro de Transfusión de Galicia) for their help with the blood samples from the healthy donors. This research was partially supported by Consellería de Educación e Ordenación Universitaria da Xunta de Galicia (CN 2011/024), and Agrupación Estratégica INBIOMED (Investigación en Biomedicina) (CN 2012/273), from DXPCTSUG (Dirección Xeral de Promoción Científica e Tecnolóxica do Sistema Universitario de Galicia) and FEDER (Fondo Europeo de Desarrollo Regional) EU funding. References [1] A.D. Singh, M.E. Turell, A.K. Topham, Uveal melanoma: trends in incidence, treatment, and survival, Ophthalmology 118 (2011) 1881–1885. [2] B. Damato, Does ocular treatment of uveal melanoma influence survival? Br. J. Cancer 103 (2010) 285–290. [3] T. Sato, Locoregional management of hepatic metastasis from primary uveal melanoma, Semin. Oncol. 37 (2010) 127–138.
[4] V. Torres, P. Triozzi, C. Eng, R. Tubbs, L. Schoenfiled, J.W. Crabb, et al., Circulating tumor cells in uveal melanoma, Future Oncol. 7 (2011) 101–109. [5] O.J. Cordero, F.J. Salgado, M. Nogueira, On the origin of serum CD26 and its altered concentration in cancer patients, Cancer Immunol. Immunother. 58 (2009) 1723–1747. [6] L. De Chiara, A.M. Rodríguez-Piñeiro, F.J. Rodríguez-Berrocal, O.J. Cordero, D. Martínez-Ares, M. Páez de la Cadena, Serum CD26 is related to histopathological polyp traits and behaves as a marker for colorectal cancer and advanced adenomas, BMC Cancer 10 (2010) 333. [7] O.J. Cordero, D. Ayude, M. Nogueira, F.J. Rodriguez-Berrocal, M.P. de la Cadena, Preoperative serum CD26 levels: diagnostic efficiency and predictive value for colorectal cancer, Br. J. Cancer 83 (2000) 1139–1146. [8] L. De Chiara, A.M. Rodríguez-Piñeiro, O.J. Cordero, L. Vázquez-Tuñas, D. Ayude, F.J. Rodríguez-Berrocal, M.P. de la Cadena, Postoperative serum levels of sCD26 for surveillance in colorectal cancer patients, PLoS One 9 (2014) e107470. [9] R. Pang, W.L. Law, A.C. Chu, J.T. Poon, C.S. Lam, A.K. Chow, L. Ng, L.W. Cheung, X.R. Lan, H.Y. Lan, V.P. Tan, T.C. Yau, R.T. Poon, B.C. Wong, A subpopulation of CD26+ cancer stem cells with metastatic capacity in human colorectal cancer, Cell Stem Cell 6 (2010) 603–615. [10] A.M. Lambeir, C. Durinx, S. Scharpé, I. De Meester, Dipeptidyl-peptidase IV from bench to bedside: an update on structural properties, functions, and clinical aspects of the enzyme DPP IV, Crit. Rev. Clin. Lab. Sci. 40 (2003) 209–294.
Rubén Varela-Calviño Mónica Imbernón1 Department of Biochemistry and Molecular Biology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain Lorena Vázquez-Iglesias María Páez de la Cadena Department of Biochemistry, Genetics and Immunology, University of Vigo, 36200 Vigo, Spain Manuel Bande-Rodríguez Antonio Piñeiro Service of Ophtalmology, University Hospital Complex of Santiago de Compostela, SERGAS, Santiago de Compostela, Spain María Pardo Obesidomics Group, IDIS (Health Research Institute of Santiago de Compostela), SERGAS, Santiago de Compostela, Spain Oscar J. Cordero⁎ Department of Biochemistry and Molecular Biology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain Corresponding author. E-mail address: [email protected]. 6 July 2015 Available online 9 July 2015
1 Present address: Department of Physiology, University of Santiago de Compostela, Spain.