Cutaneous T-cell lymphoma severity index and T-cell gene rearrangement

Multidisciplinary Management of Mycosis Fungoides/Sézary Syndrome

PURPOSE OF REVIEW

Diagnosis and management of mycosis fungoides and Sézary syndrome (MF/SS) require accurate clinicopathological correlation and a multidisciplinary approach. We reviewed major advances in the field regarding diagnostic and prognostic tools as well as skin-directed therapies (SDTs) and systemic agents for MF/SS published in the past 2 years.

RECENT FINDINGS

Improved technology (T-cell receptor high-throughput sequencing) and increased multicenter collaboration (Cutaneous Lymphoma International Consortium) have led to diagnostic/prognostic advances. Concurrently, numerous genomic studies have enhanced understanding of disease pathogenesis. Advances in SDTs include topical resiquimod, a novel potent Toll-like receptor (TLR) agonist; consensus CTCL phototherapy guidelines; and use of low-dose radiation therapy. Novel systemic therapies for advanced disease of note include targeted antibody drug conjugates (brentuximab vedotin), immune checkpoint inhibitors, and allogeneic hematopoietic stem cell transplantation (HSCT). Our "toolbox" to diagnose and treat the spectrum of MF/SS continues to expand. Further characterization of genomic data going forward will enable a rational approach to selecting and combining therapies to improve patient care.

Sézary syndrome is a unique cutaneous T-cell lymphoma as identified by an expanded gene signature including diagnostic marker molecules CDO1 and DNM3

Sezary syndrome (SS) is a rare, aggressive CD4+ cutaneous T-cell lymphoma (CTCL); molecular traits differentiating SS from nonleukemic mycosis fungoides (MF) and from inflammatory skin diseases (ID) are not sufficiently characterized. Peripheral blood mononuclear cells (PBMC) of 10 SS patients and 10 healthy donors (HD) were screened by Affymetrix U133Plus2.0 chips for differential gene expression. Ten candidate genes were confirmed by qRT-PCR to be significantly overexpressed in CD4+ T cells of SS versus HD/ID. For easier clinical use, these genes were re-analyzed in PBMC; qRT-PCR confirmed five novel (DNM3, IGFL2, CDO1, NEDD4L, KLHDC5) and two known genes (PLS3, TNFSF11) to be significantly overexpressed in SS. Multiple logistic regression analysis revealed that CDO1 and DNM3 had the highest discriminative power in combination. Upon comparison of PBMC and skin samples of SS versus MF, CDO1 and DNM3 were found upregulated only in SS. Using anti-CDO1 antisera, differential expression of CDO1 protein was confirmed in SS CD4+ T cells. Interestingly, DNM3 and CDO1 are known to be regulated by SS-associated transcription factors TWIST1 and c-myb, respectively. Furthermore, CDO1 catalyzes taurine synthesis and taurine inhibits apoptosis and promotes chemoprotection. In summary, CDO1 and DNM3 may improve the diagnosis of SS and open novel clues to its pathogenesis.

Serologic and immunohistochemical prognostic biomarkers of cutaneous malignancies

Biomarkers are important tools in clinical diagnosis and prognostic classification of various cutaneous malignancies. Besides clinical and histopathological aspects (e.g. anatomic site and type of the primary tumour, tumour size and invasion depth, ulceration, vascular invasion), an increasing variety of molecular markers have been identified, providing the possibility of a more detailed diagnostic and prognostic subgrouping of tumour entities, up to even changing existing classification systems. Recently published gene expression or proteomic profiling data relate to new marker molecules involved in skin cancer pathogenesis, which may, after validation by suitable studies, represent future prognostic or predictive biomarkers in cutaneous malignancies. We, here, give an overview on currently known serologic and newer immunohistochemical biomarker molecules in the most common cutaneous malignancies, malignant melanoma, squamous cell carcinoma and cutaneous lymphoma, particularly emphasizing their prognostic and predictive significance.

Overexpression of c-myb in Leukaemic and Non-Leukaemic Variants of Cutaneous T-Cell Lymphoma

BACKGROUND

The c-myb oncogene is a transcription factor that regulates proliferation, differentiation and apoptosis of haematopoietic cells and activated T cells by binding to promoter sequences of such genes as c-myc or bcl-2 that are expressed in cutaneous T-cell lymphoma (CTCL).

OBJECTIVE

Our study was performed in order to evaluate c-myb expression as a quantitative parameter for differential diagnosis in leukaemic and non-leukaemic variants of CTCL.

METHODS

c-myb expression was analysed in lesional skin and in the peripheral blood of 21 patients with mycosis fungoides (MF), 15 patients with Sézary syndrome (SS) and 15 patients with inflammatory skin diseases using immunohistochemistry and semiquantitative as well as quantitative RT-PCR.

RESULTS

Immunohistochemistry confirmed expression of c-myb in the lesional skin of the majority of CTCL patients with a tendency towards higher expression in SS (1.86 +/- 0.5) versus MF (1.2 +/- 0.7) while c-myb was absent from the lesional skin of patients with inflammatory skin diseases. c-myb was overexpressed in the peripheral blood in all SS patients (100% SS vs. 35.7% MF) at a high expression level (51,335.31 +/- 31,960.32 AU in SS vs. 1,226.35 +/- 1,258.29 AU in MF using semiquantitative RT-PCR, and 5.72 x 10(-2) +/- 2.27 x 10(-2) in SS vs. 0.91 x 10(-2) +/- 1.18 x 10(-2) in MF vs. 0.24 x 10(-2) +/- 0.11 x 10(-2) in inflammatory skin disease using quantitative RT-PCR). CD4+ cells from the peripheral blood of SS patients and cell lines in vitro showed the highest c-myb expression levels upon quantitative RT-PCR (23.27 x 10(-2) and 10.78 x 10(-2) +/- 7.24 x 10(-2)).

CONCLUSION

Overexpression of c-myb in skin lesions of both non-leukaemic and leukaemic CTCL independent of the stage of the disease indicates that it acts early in disease development. Nevertheless, if positive, c-myb expression in lesional skin is a clear-cut diagnostic marker for CTCL as compared to inflammatory skin diseases. High-level expression of c-myb in the peripheral blood as assessed by quantitative RT-PCR constitutes an additional diagnostic parameter for SS and may be especially useful in cases in which morphological determination of Sézary cells or FACS analysis of CD7 and CD26 remain inconclusive.

Prognostic factors and prediction of prognosis by the CTCL Severity Index in mycosis fungoides and Sezary syndrome

BACKGROUND

Cutaneous T-cell lymphoma (CTCL) is a slowly progressive malignancy for which there is no cure. Therefore, accurate prediction of prognosis is important for the conduct of clinical trials and for counselling of individuals.

OBJECTIVES

To improve prediction of survival in patients with CTCL.

METHODS

Prognostic factors including tumour-node-metastasis (TNM) criteria and the CTCL Severity Index (CTCL-SI) were analysed using a Weibull model for multivariate analysis in a sample of 62 patients with classical CTCL (mycosis fungoides and Sézary syndrome). The Brier score was used to quantify the quality of individual prediction.

RESULTS

Estimated 5-year survival rate (SR5) differed according to TNM stage: stage IA, 100% (95% confidence interval 70-100%); IB-III, 86% (73-100%); IVA, 54% (32-91%); IVB, 0% (0-52%). In a multivariate analysis, two independent prognostic factors were identified: lymph node (P = 0.036) and blood involvement (P = 0.015). A probability of survival model showed correlation of CTCL-SI with survival in patients with CTCL-SI > 20 according to the following formula: SR5 = 124-2 x (CTCL-SI)%. Calibration of SR5 against CTCL-SI-independent CTCL subsets revealed underestimation of Sézary syndrome. When CTCL-SI parameters were adjusted accordingly, the probability of survival model did not change significantly, while SR5 values became adequate. In addition, CTCL-SI was shown to be superior to TNM by 30% regarding individual predictive power.

CONCLUSIONS

Probability of survival in CTCL can be accurately predicted by a CTCL-SI-based survival rate formula. Careful monitoring of lymph node and blood compartments and quantification by CTCL-SI are reliable tools for follow-up of patients with CTCL and allow progression-adjusted prediction of prognosis.

Transition of Sézary syndrome into mycosis fungoides after complete clinical and molecular remission under extracorporeal photophoresis

Mycosis fungoides (MF) and Sezary syndrome (SS) are the most common clinical variants of cutaneous T cell lymphoma. Although thought to be closely related to mature T helper cells, the relation between the neoplastic cells in MF and SS is still not fully clarified. This report describes a patient with complete remission of SS under treatment with extracorporeal photophoresis (ECP), who subsequently developed typical plaques of MF and large cell lymphoma (LCL). Serial polymerase chain reaction analyses confirmed identical T cell receptor beta and gamma gene rearrangements in SS, MF, and LCL, and complete disappearance of the circulating malignant T cell clone from the peripheral blood after ECP. These findings indicate that the neoplastic cells in SS, MF, and LCL are derived from a common precursor T cell, despite the change in clinical phenotype.

Early TCR-beta and TCR-gamma PCR detection of T-cell clonality indicates minimal tumor disease in lymph nodes of cutaneous T-cell lymphoma: diagnostic and prognostic implications

The lymph nodes are generally the first extracutaneous manifestation in patients with cutaneous T-cell lymphoma (CTCL); however, their early involvement is difficult to assess. The aim of our study was to define the diagnostic and prognostic value of T-cell clonality analysis for a more precise assessment of lymph node involvement in CTCL. T-cell clonality was determined by 2 independent polymerase chain reaction (PCR) assays, namely a recently developed T-cell receptor-beta (TCR-beta) PCR technique as well as an established TCR-gamma PCR. T-cell clonality was found in 22 of 22 lymph nodes with histologically detectable CTCL involvement as well as in 7 of 14 histologically noninvolved dermatopathic lymph nodes. The clonal T-cell populations in the lymph nodes were in all cases identical to those detected in the corresponding skin lesions, identifying them as the tumor cell population. T-cell clonality was not found in any of the 12 dermatopathic lymph nodes from 12 patients with inflammatory skin diseases. Clonal T-cell detection in 7 of 14 dermatopathic lymph nodes of patients with CTCL was associated with limited survival (74 months; confidence interval [CI], 66-82 months) as in patients with histologically confirmed lymph node involvement (41 months; CI, 35-47 months), whereas all patients without T-cell clonality in the lymph nodes (7 patients) were alive at the last follow-up. Thus, T-cell clonality analysis is an important adjunct in differentiating benign dermatopathic lymphadenitis from early CTCL involvement.

Clonal T cell receptor gamma-chain gene rearrangement by PCR-based GeneScan analysis in the skin and blood of patients with parapsoriasis and early-stage mycosis fungoides

Cutaneous T cell lymphoma (CTCL) and reactive T cell skin diseases represent opposite ends of a spectrum of diseases ranging from overtly malignant to persistently benign. Within this spectrum, the parapsoriasis group is not clearly defined regarding malignant potential. In contrast to consistent findings in advanced-stage CTCL, clonality analysis of parapsoriasis has produced conflicting results in previous studies. As T cell receptor gamma-chain polymerase chain reaction GeneScan analysis (TCR-gamma-PCR-GSA) stands out by its sensitivity, its accuracy in size determination of PCR products, its capacity to identify false positives by repeated analysis and its easy applicability, this approach was used to analyse the clonality status of 41 patients with borderline T cell lymphoproliferative skin diseases, including parapsoriasis (n=27) and early-stage mycosis fungoides (MF) (n=14). A monoclonal T cell infiltrate was demonstrated by repeated TCR-gamma-PCR-GSA in lesional skin specimens in 19.2% of parapsoriasis patients and in 66.6% of early-stage MF cases (p=0.013). In peripheral blood, a monoclonal T cell population was found in a similar percentage of parapsoriasis and of early-stage MF patients (26.7% versus 12.5%; p=0.611). A detailed analysis of parapsoriasis subentities, namely small and large plaque parapsoriasis, and parapsoriasis lichenoides, revealed monoclonality in 2(6)/2(5), 3(14)/2(8) and 0(6)/0/(3) of the skin and peripheral blood specimens, respectively. The high detection rate of false positive cases by repeated analysis (20-37.5%) provides a corrected perspective for the high rates of dominant T cell clones found by others in the peripheral blood of such patients. From the results obtained, three major conclusions can be drawn: firstly, CTCL is clearly associated with detection of monoclonality, even in its early stages; secondly, monoclonality is not a prerequisite for potential CTCL precursor entities; and thirdly, recirculating malignant T cells identical to the skin clone are not readily detected in parapsoriasis or early-stage MF, but may rather indicate disease progression.

High detection rate of T-cell receptor beta chain rearrangements in T-cell lymphoproliferations by family specific polymerase chain reaction in combination with the GeneScan technique and DNA sequencing

The distinction between benign polyclonal and malignant monoclonal lymphoid disorders by morphology or immunophenotyping is frequently difficult. Therefore, the demonstration of clonal B-cell or T-cell populations by detecting identically rearranged immunoglobulin (Ig) or T-cell receptor (TCR) genes is often used to solve this diagnostic problem. Whereas the detection of rearranged Ig genes is well established, TCR gamma (γ) and beta (β) gene rearrangements often escape detection with the currently available polymerase chain reaction (PCR) assays. To establish a sensitive, specific, and rapid method for the detection of rearranged TCR-β genes, we developed a new PCR approach with family-specific Jβ primers and analyzed the resulting PCR products by high-resolution GeneScan technique. The superior efficiency of this new method was demonstrated by investigating 132 DNA samples extracted from lymph node and skin biopsy specimens (mostly formalin fixed) and blood samples of 62 patients who had a variety of T-cell lymphomas and leukemias. In all but 1 of the tumor samples (98.4%) a clonal amplificate was detectable after TCR-β PCR and the same clonal T-cell population was also found in 15 of 18 (83%) of the regional lymph nodes and in 7 of 11 (64%) of the peripheral blood samples. Direct comparison of these results with those obtained currently by the most widely applied TCR-γ PCR revealed an approximate 20% lower detection rate in the same set of samples than with the TCR-β PCR method. These results indicate that the new TCR-β PCR is most suitable for a rapid and reliable detection of clonal T-cell populations.

High detection rate of T-cell receptor beta chain rearrangements in T-cell lymphoproliferations by family specific polymerase chain reaction in combination with the GeneScan technique and DNA sequencing

The distinction between benign polyclonal and malignant monoclonal lymphoid disorders by morphology or immunophenotyping is frequently difficult. Therefore, the demonstration of clonal B-cell or T-cell populations by detecting identically rearranged immunoglobulin (Ig) or T-cell receptor (TCR) genes is often used to solve this diagnostic problem. Whereas the detection of rearranged Ig genes is well established, TCR gamma (γ) and beta (β) gene rearrangements often escape detection with the currently available polymerase chain reaction (PCR) assays. To establish a sensitive, specific, and rapid method for the detection of rearranged TCR-β genes, we developed a new PCR approach with family-specific Jβ primers and analyzed the resulting PCR products by high-resolution GeneScan technique. The superior efficiency of this new method was demonstrated by investigating 132 DNA samples extracted from lymph node and skin biopsy specimens (mostly formalin fixed) and blood samples of 62 patients who had a variety of T-cell lymphomas and leukemias. In all but 1 of the tumor samples (98.4%) a clonal amplificate was detectable after TCR-β PCR and the same clonal T-cell population was also found in 15 of 18 (83%) of the regional lymph nodes and in 7 of 11 (64%) of the peripheral blood samples. Direct comparison of these results with those obtained currently by the most widely applied TCR-γ PCR revealed an approximate 20% lower detection rate in the same set of samples than with the TCR-β PCR method. These results indicate that the new TCR-β PCR is most suitable for a rapid and reliable detection of clonal T-cell populations.

Follicular mycosis fungoides

We describe a patient with follicular mycosis fungoides (MF), a rare folliculotropic variant of cutaneous T-cell lymphoma (CTCL). Follicular involvement in CTCL usually presents clinically as alopecia mucinosa associated histologically with follicular mucinosis. Follicular MF differs from alopecia mucinosa/follicular mucinosis associated with MF with regard to its clinical presentation, histology and, presumably, prognosis. Our patient presented with the characteristic findings of follicular MF, i.e. infiltrated plaques showing numerous enlarged, comedo-like follicular infundibula; histology was dominated by exclusive folliculotropism of atypical lymphocytes sometimes forming follicular Pautrier's microabscesses, and by lack of epidermotropism and follicular mucinosis. Despite photochemotherapy and treatment with oral retinoids and interferon alpha, the patient's follicular MF rapidly developed into a progressive CTCL with large tumorous lesions, but responded to electron beam therapy. The course of our patient's disease confirms the notion that follicular MF may be associated with a worse prognosis than classical MF. However, electron beam irradiation induced remission of follicular MF that was maintained by a combination therapy consisting of extracorporeal photopheresis and interferon alfa.

Clonal T-cell receptor gamma-chain gene rearrangement by PCR-based GeneScan analysis in advanced cutaneous T-cell lymphoma: a critical evaluation

Detection of clonal T-cell receptor gamma (TCRgamma)-chain gene rearrangement is a promising approach to distinguish between cutaneous T-cell lymphomas (CTCLs) and reactive T-cell infiltrates. Despite the improved sensitivity by using the polymerase chain reaction (PCR) rather than Southern blot analysis, monoclonality could be demonstrated in only 53-90 per cent of CTCL biopsies in recent studies. In the present study, formalin-fixed, paraffin-embedded specimens of 21 selected patients with clear-cut advanced-stage CTCL were analysed using a semi-nested TCRgamma PCR with newly developed consensus primer pairs. Detection of PCR products was done by GeneScan analysis (GSA); this technique is advantageous due to its sensitivity and accuracy in the detection and size determination of PCR products and it is easier to interpret than direct read-outs from TGGE or DGGE gels. In serial dilution experiments, TCRgamma-PCR-GSA allowed the detection of clonal, rearranged T-cells with a high in vitro sensitivity against a polyclonal background (1-6 per cent). Despite the selection of clear-cut, advanced-stage CTCL cases, however, dominant clonal TCRgamma-chain gene rearrangement was found in only 16 of the 21 patients analysed, indicating an overall clinical sensitivity of 76 per cent. Specificity was evaluated using biopsy specimens from 21 control patients suffering from long-standing psoriasis (n=13) and eczema (n=8). Surprisingly, GeneScan profiles showing apparently single dominant peaks were detected in 14 per cent of these skin lesions, but these profiles turned out to be pseudo-monoclonal by repeated determinations. In conclusion, TCRgamma-PCR-GSA does not suffice reliably to exclude malignancy, due to its limited clinical sensitivity, but with precautions taken to detect pseudo-monoclonality and to secure specificity, TCRgamma-PCR-GSA is a valuable instrument in the diagnosis of CTCL.