Clusterin Expression Correlates With Stage and Presence of Large ...

Anatomic Pathology / Clusterin Expression in Mycosis Fungoides

Clusterin Expression Correlates With Stage and Presence of Large Cells in Mycosis Fungoides Pranil Chandra, DO,1 Jose A. Plaza, MD,2,4 Zhuang Zuo, MD, PhD,1 A. Hafeez Diwan, MD, PhD,2 Hartmut Koeppen, MD, PhD,1 Madeleine Duvic, MD,3 L. Jeffrey Medeiros, MD,1 and Victor G. Prieto, MD, PhD2 Key Words: Mycosis fungoides; Clusterin; T-cell lymphoma; Anaplastic large cell lymphoma DOI: 10.1309/AJCPH43ZDVLSOSNB

Abstract Clusterin expression is common in systemic and cutaneous anaplastic large cell lymphoma (ALCL). Mycosis fungoides (MF) in large cell transformation can resemble ALCL. In this study, we immunohistochemically assessed for clusterin in 97 skin biopsy specimens, including 70 MF cases and 27 other cutaneous neoplasms including ALCL, peripheral T-cell lymphoma unspecified (PTCL), and lymphomatoid papulosis (LyP). Clusterin was positive in 36 (51%) of 70 cases of MF and correlated with clinical stage in 68 cases: 3 of 21 stage I, 11 of 20 stage II, and 23 of 27 stage III/IV. Clusterin expression also correlated with type of skin lesion (3/19 patch, 13/28 plaque, and 20/23 tumor/erythroderma) and number of large cells (6/30 small cell, 12/18 with increased large cells, and 18/22 with large cell transformation). Clusterin expression was not specific for MF as it also was positive in 3 of 3 cases of LyP, 2 of 2 systemic ALCL cases involving skin, 7 of 16 cutaneous ALCLs, and 1 of 6 PTCLs.

© American Society for Clinical Pathology

Mycosis fungoides (MF) is the most common type of lymphoma to involve the skin. Clinically, patients with MF present in the early stages with patch and/or plaque lesions involving primarily the trunk.1,2 These lesions can persist for years, after which they may progress to tumor stage and, rarely, to a generalized erythroderma/Sézary syndrome. Histologically, MF usually begins as an epidermotropic infiltrate of small lymphocytes with irregular, cerebriform nuclei. However, in up to 50% of patients with MF, large cell transformation develops, defined as a lesion composed of more than 25% large lymphoid cells.3 MF with large cell transformation correlates with the clinical development of tumors and is often associated with a poor clinical outcome.4 Clusterin is a ubiquitously expressed glycoprotein that was first isolated from ram rete testes fluid and was named because of its ability to induce clustering of Sertoli cells.5 A number of studies have shown that clusterin is expressed by anaplastic large cell lymphoma (ALCL), the systemic and cutaneous types, which can be useful in distinguishing ALCL from other tumors it may resemble such as classical Hodgkin lymphoma.6-9 Typical cases of MF do not express clusterin. However, MF may transform into a large cell, anaplastic neoplasm that can mimic cutaneous ALCL. In an earlier study, Saffer et al10 observed such a case that strongly expressed clusterin. This finding led us to hypothesize that clusterin may be useful as a marker of progression in MF. In the present study, we analyzed for clusterin expression in a total of 97 skin biopsy specimens involved by T-cell lymphoproliferations including 70 cases of MF in different clinical stages and with more or fewer large cells. Our results show that clusterin expression correlates with stage and number of large cells in MF.

511

Am J Clin Pathol 2009;131:511-515 DOI: 10.1309/AJCPH43ZDVLSOSNB

511 511

Chandra et al / Clusterin Expression in Mycosis Fungoides

Materials and Methods Approval for this study was obtained from The University of Texas M. D. Anderson Cancer Center Institutional Review Board (Houston). Paraffin blocks of 97 skin biopsy specimens involved by T-cell lymphoproliferations were identified in the files of the Department of Hematopathology, including 70 cases of MF (19 patch stage, 28 plaque stage, 21 tumor stage, and 2 with erythroderma), 16 cutaneous ALCLs, 2 systemic ALCLs involving skin, 6 peripheral T-cell lymphomas (PTCLs), and 3 cases of lymphomatoid papulosis. Clusterin expression was assessed using immunohistochemical methods described previously.10 A case was scored as positive for clusterin when neoplastic cells exhibited a cytoplasmic or paranuclear (dot-like) pattern of staining. All cases were classified according to the criteria specified in the World Health Organization classification. The diagnosis was, therefore, based on clinical, histologic, and immunophenotypic results, with results of molecular studies to assess clonality in some cases. Clinical stage was determined by using the system recommended by the International Society for Cutaneous Lymphomas and the European Organization for Research and Treatment of Cancer.11 The methods used for routine immunohistochemical studies and for molecular studies to assess the T-cell receptor γ chain gene have been described previously.12,13 Cases of MF were also categorized according to the type of lesion (patch, plaque, and tumor/ erythroderma) and the number of large cells. Lesions with increased numbers of large cells had more than 10% but fewer than 25% large cells. Cases of MF in large cell transformation had more than 25% large cells.14 Statistical differences were calculated by using χ2 analysis and the Fisher exact test.

Results Clusterin expression in the various cutaneous T-cell lymphoproliferations is summarized in zTable 1z. Clusterin was positive in 36 (51%) of 70 MF specimens. The percentage of

zTable 1z Summary of Clusterin Expression in Cutaneous T-Cell Lymphoproliferations Diagnosis

No. of Cases

Mycosis fungoides Patch Plaque Tumor Anaplastic large cell lymphoma Systemic Cutaneous Lymphomatoid papulosis Peripheral T-cell lymphoma Total

512 512


70 19 28 23 18 2 16 3 6 97

No. (%) of Cases Positive for Clusterin 36 (51) 3 (16) 13 (46) 20 (87) 9 (50) 2 (100) 76 (44) 3 (100) 1 (17) 49 (51)

clusterin-positive cells ranged from 5% to 80% with a mean of 22% positive cells. In cases of MF with increased numbers of large cells, clusterin was preferentially expressed in the larger cells. Stromal cells within the dermis also variably expressed clusterin. Clusterin expression correlated with the clinical stage, the type of skin lesion (or histologic stage), and the presence of large cells zImage 1z. Data were available for determining clinical stage in 68 cases: 3 (14%) of 21 with stage I, 11 (55%) of 20 with stage II, and 23 (85%) of 27 with stage III/ IV MF cases were clusterin-positive. Clusterin expression was also found in histologically progressed cases of MF: 3 (16%) of 19 patch lesions, 13 (46%) of 28 plaque lesions, and 20 (87%) of 23 tumors/erythroderma were clusterin-positive. According to cytologic composition, 30 (43%) of 70 MF cases showed predominantly small cells, 18 (26%) were MF with increased numbers of large cells, and 22 (31%) were MF in large cell transformation: 6 (20%) of 30 small cell MF cases were clusterin-positive vs 12 (67%) of 18 MF cases with increased numbers of large cells and 18 (82%) of 22 cases of MF in large cell transformation. These differences in clusterin expression were statistically significant zTable 2z. In cases of tumor-stage MF and MF in large cell transformation, clusterin expression was more prominent in the deeper portion of the neoplastic infiltrate. Clusterin was also positive in 3 (100%) of 3 cases of lymphomatoid papulosis and 2 (100%) of 2 cases of systemic ALCL involving skin, 7 (44%) of 16 cases of cutaneous ALCL, and 1 (17%) of 6 cases of PTCL. The case of PTCL that expressed clusterin was a cutaneous γδ T-cell lymphoma that exhibited clusterin expression by small and large lymphocytes.

Discussion Clusterin is a ubiquitous glycoprotein that is also known by a number of other names, such as glycoprotein III, apolipoprotein J, ionizing radiation–induced protein-8, SP-40, complement lysis inhibitor, gp80, testosterone-repressed prostate message-2, and sulfated glycoprotein-2.15,16 Clusterin has a molecular weight of 80 kDa and is encoded by a gene located on chromosome 8p21. A variety of functions for clusterin have been suggested, including complement regulation, cell aggregation, DNA repair, cell survival and proliferation, apoptosis, and cell cycle control.15-17 These varied observations may be explained by 2 clusterin protein isoforms with distinct biologic activities: a glycosylated secreted form that is thought to be prosurvival and a nonsecreted form shown to be proapoptotic. A number of groups have shown that clusterin expression, as detected by immunohistochemical staining, has diagnostic usefulness in the differential diagnosis of malignant lymphomas. In particular, systemic and cutaneous ALCL are © American Society for Clinical Pathology

Anatomic Pathology / Original Article

A

B

C

D

E

zImage 1z A and B, Mycosis fungoides patch stage (A, H&E, ×200) showing negative immunostaining for clusterin, which is staining stromal cells (B, clusterin, ×200). C, D, and E, Mycosis fungoides plaque stage with increased large cells (C, H&E, ×200) showing scattered large neoplastic cells (D, H&E, ×400) positive for clusterin (E, clusterin, ×400).

© American Society for Clinical Pathology

513


513 513

Chandra et al / Clusterin Expression in Mycosis Fungoides

F

G

H

zImage 1z (cont) F, G, and H, Mycosis fungoides tumor stage with large cell transformation in a case that was CD30+. Tumor stage mycosis fungoides (F, H&E, ×100) demonstrating more than 25% large cells (G, H&E, ×400). Clusterin immunostain demonstrates predominantly Golgi and occasional cytoplasmic expression (H, clusterin, ×200).

commonly positive for clusterin, unlike other large cell lymphoid lesions.6-9 In an earlier study, Saffer et al10 observed clusterin expression in a case of MF that had transformed to a large anaplastic tumor that was CD30+. In addition, changes in clusterin expression have been associated with tumor progression and adverse outcomes in patients with a number of solid tumors.18-20 For these reasons, we investigated cases of MF for clusterin expression to determine if clusterin had any value in assessing for transformation. More than 50% of cases of MF in this study expressed clusterin, and expression correlated with clinical stage, the histologic type of lesion, and the number of large cells. Fewer than 20% of patients with clinical stage I disease had MF lesions that expressed clusterin compared with 85% of patients with clinical stage III/IV disease. Similarly approximately 20% of small cell or patch-stage MF lesions expressed clusterin, compared with 82% of MF in large cell transformation and 87% of MF tumors/erythroderma. Anecdotally, 514 514


the disease in 2 patients in this study with patch-stage and 1 patient with plaque-stage MF positive for clusterin later progressed to large cell transformation of MF. Whether clusterin has a direct role in transformation or is simply a marker that can aid in recognition of transformation cannot be determined from this study. In addition, many of the biopsy specimens in this study were follow-up specimens from patients with a known diagnosis of MF and who had been treated with cytotoxic chemotherapy. This may suggest that the observed increase in clusterin is a stress-related response. Furthermore, in vitro studies have shown clusterin to be up-regulated in cell lines following exposure to cytotoxic chemotherapeutics.21 Against this possibility, 3 patients with MF in large cell transformation had not received therapy before diagnosis and, in these cases, clusterin expression cannot be attributed to a therapy-induced stress response. Further studies are needed to better understand the potential role of clusterin expression in the MF setting. © American Society for Clinical Pathology

Anatomic Pathology / Original Article

zTable 2z Statistical Differences in Clusterin Expression in Mycosis Fungoides

P*

Category

By clinical stage I vs II II vs III/IV I vs III/IV By histologic stage Patch vs plaque Plaque vs tumor Patch vs tumor By cytologic composition Small cell vs increased large cells Increased large cells vs large cell transformation Large cell transformation vs small cell

*

.0156 .0503