Role of chromatin assembly factor-1/p60 and poly [ADP-ribose] polymerase 1 in mycosis fungoides.

Mycosis fungoides (MF) represents the most common type of cutaneous lymphoma. In the majority of patients, the disease has a slow evolution and a protracted course; however, a subset of patients shows poor oncologic outcomes. Unfortunately, there are no reliable prognostic markers for MF, and the currently available treatments are only effective in a minority of patients. This study aimed to evaluate the expression and clinical significance of PARP-1 and CAF-1/p60 in MF. Sixty-four MF representatives of the different stages of disease were assessed by immunohistochemistry for PARP-1 and CAF-1/p60. The association of PARP-1 and CAF-1/p60 with the MF stage and outcome was assessed by using Fisher's exact test and Kaplan-Meier survival analysis with the Log-rank test; a p value < 0.05 was considered significant. PARP-1 was overexpressed in 57.9% of MF and was significantly associated with a MF stage > II (p = 0.034) but not with the risk of death (p = 0.237). CAF-1/p60 was overexpressed in 26.8% of MF and was significantly associated with decreased overall survival (p < 0.001) but not with the MF stage (p = 1). A significant association was found between PARP-1 overexpression and CAF-1/p60 overexpression (p = 0.0025). Simultaneous overexpression of PARP-1 and CAF-1/p60 was significantly associated with decreased overall survival (p < 0.001), although less strongly than CAF-1/p60 alone (χ2 = 14.916 vs 21.729, respectively). In MF, PARP-1 is overexpressed in advanced stages, while CAF-1/p60 is overexpressed in the cases with shorter overall survival, appearing as a significant prognostic marker. A role for PARP-1 inhibitors and anti-CAF-1/p60 targeted therapy may be reasonably hypothesized in MF.

Current status of histone deacetylase inhibitors in cutaneous T-cell lymphoma.

Cutaneous T cell lymphoma (CTCL) is a non-Hodgkin's lymphoma with a heterogenous presentation and highly variable disease course. The most common subtypes of CTCL are mycosis fungoides (MF) and Sézary Syndrome (SS). Treatment varies based on the stage of the disease with skin directed therapies typically utilized for early stage disease, and systemic therapies employed for more advanced disease. There are few highly effective treatments available, and systemic therapies have limited response rates. Histone deacetylase inhibitors have emerged as mainstream treatments for MF/SS over the past several years. Here, we discuss the mechanism of action of histone deacetylase inhibitors in relation to the pathogenesis of MF/SS, evaluate the clinical trials that led to Food and Drug Administration approval of two of the histone deacetylase inhibitors for MF/SS and describe the results for those still under investigation. Additionally, we discuss the potential for combination therapies in order to optimize outcomes of treatment with histone deacetylase inhibitors.

Genomic analysis reveals recurrent deletion of JAK-STAT signaling inhibitors HNRNPK and SOCS1 in mycosis fungoides.

Mycosis fungoides (MF) is the most common cutaneous T-cell lymphoma (CTCL). Causative genetic alterations in MF are unknown. The low recurrence of pathogenic small-scale mutations (ie, nucleotide substitutions, indels) in the disease, calls for the study of additional aspects of MF genetics. Here, we investigated structural genomic alterations in tumor-stage MF by integrating whole-genome sequencing and RNA-sequencing. Multiple genes with roles in cell physiology (n = 113) and metabolism (n = 92) were found to be impacted by genomic rearrangements, including 47 genes currently implicated in cancer. Fusion transcripts involving genes of interest such as DOT1L, KDM6A, LIFR, TP53, and TP63 were also observed. Additionally, we identified recurrent deletions of genes involved in cell cycle control, chromatin regulation, the JAK-STAT pathway, and the PI-3-K pathway. Remarkably, many of these deletions result from genomic rearrangements. Deletion of tumor suppressors HNRNPK and SOCS1 were the most frequent genetic alterations in MF after deletion of CDKN2A. Notably, SOCS1 deletion could be detected in early-stage MF. In agreement with the observed genomic alterations, transcriptome analysis revealed up-regulation of the cell cycle, JAK-STAT, PI-3-K and developmental pathways. Our results position inactivation of HNRNPK and SOCS1 as potential driver events in MF development.

Catalase, carbonic anhydrase and xanthine oxidase activities in patients with mycosis fungoides.

Mycosis fungoides (MF) is the most common form of cutaneous T-cell lymphoma. In several studies the relationship between catalase (CAT), human cytosolic carbonic anhydrases (CA; hCA-I and hCA-II) and xanthine oxidase (XO) enzyme activities have been investigated in various types of cancers but carbonic anhydrase, catalase and xanthine oxidase activities in patients with MF have not been previously reported. Therefore, in this preliminary study we aim to investigate CAT, CA and XO activities in patients with MF. This study enrolled 32 patients with MF and 26 healthy controls. According to the results, CA and CAT activities were significantly lower in patients with mycosis fungoides than controls (p < 0.001) (p < 0.001). There was no significant difference in XO activity between patient and control group (p = 0.601). Within these findings, we believe these enzyme activity levels might be a potentially important finding as an additional diagnostic biochemical tool for MF.

Telomerase functions beyond telomere maintenance in primary cutaneous T-cell lymphoma.

Telomere erosion may be counteracted by telomerase. Here we explored telomere length (TL) and telomerase activity (TA) in primary cutaneous T-cell lymphoma (CTCL) by using quantitative polymerase chain reaction and interphase quantitative fluorescence in situ hybridization assays. Samples from patients with Sézary syndrome (SS), transformed mycosis fungoides (T-MF), and cutaneous anaplastic large cell lymphoma were studied in parallel with corresponding cell lines to evaluate the relevance of TL and TA as target candidates for diagnostic and therapeutic purposes. Compared with controls, short telomeres were observed in aggressive CTCL subtypes such as SS and T-MF and were restricted to neoplastic cells in SS. While no genomic alteration of the hTERT (human telomerase catalytic subunit) locus was observed in patients' tumor cells, TA was detected. To understand the role of telomerase in CTCL, we manipulated its expression in CTCL cell lines. Telomerase inhibition rapidly impeded in vitro cell proliferation and led to cell death, while telomerase overexpression stimulated in vitro proliferation and clonogenicity properties and favored tumor development in immunodeficient mice. Our data indicate that, besides maintenance of TL, telomerase exerts additional functions in CTCL. Therefore, targeting these functions might represent an attractive therapeutic strategy, especially in aggressive CTCL.

Expression of PTEN in mycosis fungoides and correlation with loss of heterozygosity.

BACKGROUND: Mycosis fungoides (MF) exhibits a variety of underlying molecular defects including aberrations involving the PTEN tumor suppressor gene. Specifically, loss of heterozygosity of PTEN has been previously demonstrated. We hypothesize that abnormalities of PTEN may result in altered immunohistochemical expression of its protein product. METHODS: Thirty-six MF specimens were stained with monoclonal antibody against PTEN protein. The percentage of nuclei retaining PTEN expression and the staining intensity was recorded. RESULTS: Average percentage of lymphoma cells retaining expression of the PTEN protein was 92% within patch-stage lesions, 81.4% in plaque-stage lesions, and 81.1% in tumor-stage lesions. Average intensity of staining for patch-stage lesions was 2.90, 2.50 for plaque lesions and 2.44 for tumor lesions. Cases lacking loss of heterozygozity at PTEN (n = 6) had an average expression of 81% and an average intensity of staining of 2.42. Whereas, cases with loss of heterozygozity at PTEN (n = 6) had an average expression of 75% of cells with an average staining intensity of 2.33. CONCLUSIONS: The percentage of cells retaining PTEN and staining intensity decrease from patch- to plaque-stage lesions, whereas both parameters show mild diminution in tumor lesions compared with plaque lesions. PTEN expression in a small sample seems to correlate with previous demonstration of loss of heterozygosity at the molecular level. Although a trend for loss of PTEN expression exists with histologic progression of MF, the effect is modest and may not represent the pivotal defect in MF pathogenesis.

Phase I clinical trial of O6-benzylguanine and topical carmustine in the treatment of cutaneous T-cell lymphoma, mycosis fungoides type.

OBJECTIVES: To evaluate the toxic effects and maximum tolerated dose of topical carmustine [1,3-bis(2-chloroethyl)-1-nitrosourea] following intravenous O6-benzylguanine in the treatment of cutaneous T-cell lymphoma (CTCL), and to determine pharmacodynamics of O6-alkylguanine DNA alkyltransferase activity in treated CTCL lesions. DESIGN: Open-label, dose-escalation, phase I trial. SETTING: Dermatology outpatient clinic and clinical research unit at a university teaching hospital. PATIENTS: A total of 21 adult patients (11 male, 10 female)with early-stage (IA-IIA) refractory CTCL, mycosis fungoides type, treated with topical carmustine following intravenous O6-benzylguanine. INTERVENTION: Treatment once every 2 weeks with 120 mg/m(2) intravenous O6-benzylguanine followed 1 hour later by whole-body, low-dose topical carmustine starting at 10 mg, with 10-mg incremental dose-escalation in 3 patient cohorts. Cutaneous T-cell lymphoma lesional skin biopsy specimens were taken at baseline and 6 hours, 24 hours, and 1 week after the first O6-benzylguanine infusion for analysis of O6-alkylguanine-DNA alkyltransferase activity. MAIN OUTCOME MEASURES: Clinical response measured by physical examination and severity-weighted assessment tool measurements, safety data acquired by review of adverse events at study visits, and O6-alkylguanine-DNA alkyltransferase activity in treated lesion skin biopsy specimens. RESULTS: A minimal toxic effect was observed through the 40-mg carmustine dose level with 76% of adverse events being grade 1 based on the National Cancer Institute Common Terminology Criteria for Adverse Events. Mean baseline O6-alkylguanine-DNA alkyltransferase activity in CTCL lesions was 3 times greater than in normal controls and was diminished by a median of 100% at 6 and 24 hours following O6-benzylguanine with recovery at 1 week. Clinical disease reduction correlated positively with O6-alkylguanine-DNA alkyltransferase activity at 168 hours (P=.02) and inversely with area under the curve of O6-alkylguanine-DNA alkyltransferase over 1 week (P=.01). Twelve partial responses and 4 complete responses were observed (overall response, 76% [95% CI, 0.55-0.89]). Five patients discontinued therapy owing to adverse events with a possible, probable, or definite relationship to the study drug. CONCLUSION: O6-benzylguanine significantly depletes O6-alkylguanine-DNA alkyltransferase in CTCL lesions and in combination with topical carmustine is well tolerated and shows meaningful clinical responses in CTCL at markedly reduced total carmustine treatment doses.

High expression of Dicer reveals a negative prognostic influence in certain subtypes of primary cutaneous T cell lymphomas.

BACKGROUND: Aberrant expression of microRNAs (miRNAs) has been implicated in oncogenesis of various tumors and primary cutaneous T cell lymphomas. Dicer, a ribonuclease III-like enzyme is essential for miRNA processing. OBJECTIVE: We initiated a retrospective study to characterize the alterations in the expression profile of Dicer in patients with primary cutaneous T cell lymphomas (CTCL). METHODS: A total of 50 consecutive patients with primary CTCL were studied, with the majority having mycosis fungoides (n=34). Five patients had primary cutaneous CD 30+ anaplastic large cell lymphoma, four patients each had lymphomatoid papulosis and primary cutaneous CD4-positive small/medium T-cell lymphoma, one primary cutaneous γδ T cell lymphoma, one Sézary syndrome and another subcutaneous panniculitis-like T cell lymphoma of αß-phenotype. Immunohistochemistry was performed on paraffin sections using a commercially available antibody against Dicer. Intensity of expression was correlated with clinical parameters including disease specific survival (DSS) and time to progression (TTP). RESULTS: After a median follow-up of 74 months (range: 1-271), 12/50 patients (24%) have died. Univariate and multivariate analysis for disease-specific survival showed Dicer expression and stage as a negative predictive factor in the sole group of MF patients (n=34) as well as in the heterogeneous group of patients (n=50), but not gender, histological subtype, primary localization of disease, age and recurrence of lymphoma (p>0.05). CONCLUSION: Our data suggest Dicer expression as a possible molecular marker in patients with MF and apparently indicate that miRNA(s) might be of clinical relevance in CTCL.

Plasma TM2-PK levels in mycosis fungoides patients.

Aerobic glycolysis increases in tumor cells and pyruvate kinase (PK) is one of the key enzymes involved; PK exists in different isoforms in various tissues. Tumor M2-PK (TM2-PK) is one of these isoforms and its expression has been observed in various tumor cells, including lymphocytes, and in lymphoproliferative disorders. The present study aimed to compare plasma levels of TM2-PK and serum levels of two established markers of various lymphoproliferative disorders-lactate dehydrogenase (LDH) and ß-2 microglobulin, and to evaluate the role of TM2-PK in drug monitorization and disease activity in mycosis fungoides (MF) patients. The study included 27 MF patients and 46 healthy controls. Among the MF patients, 18 were stage IA, 6 were stage IB, 1 was stage IIA, and 2 were stage III. Plasma TM2-PK, and serum LDH and ß-2 microglobulin levels in the patients and controls were measured using the ELISA technique, a kinetic method, and a chemiluminescent assay, respectively. Measurements were repeated in the patient group posttreatment. Median levels of TM2-PK, LDH, and ß-2 microglobulin level in the MF patients were 22 U mL⁻¹, 375 U L⁻¹, and 1,831 ng mL⁻¹, respectively. TM2-PK and ß-2 microglobulin levels did not significantly differ between the MF patients and controls; however, LDH levels were significantly higher in the MF patients. TM2-PK levels in 17 of the MF patients that were in remission did not significantly differ from their pre-therapy levels. Based on a cut-off point of 17.5 U mL⁻¹, the sensitivity and specificity of TM2-PK for diagnosing MF were 55.6 and 60.9%, respectively. ß-2 microglobulin was the most sensitive marker for diagnosing MF (63%), while LDH was the most specific marker. Furthermore, the sensitivity of TM2-PK increased when it was analyzed in combination as parallel tests with LDH and ß-2 microglobulin (86%), while the specificity was measured as 32%. In serial analysis, the specificity was increased to 98%, while the sensitivity was 5%. Statistically significant agreement in diagnosing MF was also noted between TM2-PK and LDH levels. TM2-PK may not be a useful marker for MF, especially in early-stage patients, because it proliferates slowly. We think that TM2-PK levels should be investigated in advanced-stage MF or in other types of cutaneous T-cell lymphomas; in particular, in combination with other established markers.

Immunohistochemical detection of protein gene product 9.5 (PGP 9.5) in canine epitheliotropic T-cell lymphoma (mycosis fungoides).

Protein gene product 9.5 (PGP 9.5), a ubiquitin COOH-terminal hydrolase initially considered specific for neural and neuroendocrine tissues, is expressed in a variety of epithelial and mesenchymal tumors. During immunohistochemical evaluation of a cutaneous epitheliotropic T-cell lymphoma (mycosis fungoides [MF]) in a dog, strong reactivity for PGP 9.5 was observed. This unexpected result prompted us to examine PGP 9.5 immunoreactivity in 13 additional cases of canine mycosis fungoides. All tumors were confirmed as T-cell epitheliotropic lymphoma by histopathology and immunohistochemistry for CD3. Eight of 14 cases were positive for PGP 9.5, with reactivity mainly in the cytoplasm and less commonly in the nucleus. One case had strong reactivity in the cell membrane, sometimes with concurrent paranuclear staining. Immunoreactivity did not correlate with location (epidermal, dermal, and adnexal) of tumor cells. Disease outcome did not vary between PGP 9.5-positive and negative tumors. Although PGP 9.5 immunoreactivity in MF did not predict tumor behavior in these dogs, it has had prognostic value in certain human carcinomas. This unexpected staining of lymphocytes in mycosis fungoides with an antibody to PGP 9.5 demonstrates its presence in nonneuroendocrine tumors and precludes its use as the sole diagnostic marker in discrete cell tumors in the skin.

Cloning of a gene for a novel epithelium-specific cytosolic phospholipase A2, cPLA2delta, induced in psoriatic skin.

Psoriasis is a common skin disease characterized by hyperplastic regenerative epidermal growth and infiltration of immunocytes. The etiology of psoriasis is unknown, although several genetic and cellular factors have been elucidated. To find new psoriasis-related genes, we have cloned cDNAs that are differentially expressed between normal and psoriatic skins. Among these clones, we have identified a new gene that codes for a new member of the type IV cytosolic phospholipase A(2) (cPLA(2)) family. We refer to this gene as cPLA(2)delta. It encodes a polypeptide of 818 amino acids that has significant homology with known cPLA(2) proteins in the C2 and catalytic domains. The cPLA(2)delta gene was mapped to the 15q13-14 chromosomal locus, near to the locus of the cPLA(2)beta gene, from which it is separated by a physical distance of about 220 kb. To identify the phospholipase A(2) activity of cPLA(2)delta, we transfected COS-7 cells with His-tagged cPLA(2)delta. The cell lysate from these cells had calcium-dependent phospholipase A(2) activity. Northern blot analysis revealed that a cPLA(2)delta transcript of about 4 kb is expressed in stratified squamous epithelia, such as those in skin and cervix, but not in other tissues. In situ hybridization and immunohistochemistry revealed that cPLA(2)delta is expressed strongly in the upper spinous layer of the psoriatic epidermis, expressed weakly and discontinuously in atopic dermatitis and mycosis fungoides, and not detected in the epidermis of normal skin; cPLA(2)alpha is not detected in either normal or psoriatic skin. These results suggest that cPLA(2)delta exhibits a unique distribution pattern compared with that of known cPLA(2) subtypes, and it may play a critical role in inflammation in psoriatic lesions.

Detection of telomerase activity in patients with mycosis fungoides.

OBJECTIVES: To detect telomerase activity in patients with mycosis fungoides (MF) and to study the role of telomerase in the tumorigenesis of MF. METHODS: The technique of PCR-ELISA was employed to detect telomerase activity in 35 patients with various stages of MF. RESULTS: 92.3% tumor stage of MF, 78.6% plaque stage of MF and 75.0% patch stage of MF had positive telomerase activity. The control samples had no telomerase activity. Telomerase activity in tumor stage of MF was significantly higher than that in plaque stage, while the latter was higher than that in patch stage. Telomerase activity was correlated with the stage of MF. CONCLUSION: High level of telomerase activity frequently occurred in patients with MF, suggesting that telomerase might play an important role in the tumorigenesis of MF and is a useful marker for the diagnosis of MF possibly.

The serine protease granzyme M is preferentially expressed in NK-cell, gamma delta T-cell, and intestinal T-cell lymphomas: evidence of origin from lymphocytes involved in innate immunity.

Granzyme M (GM) is a novel serine protease whose expression is highly restricted to natural killer (NK) cells, CD3(+)CD56(+) T cells, and gamma delta T cells. Using a GM-specific monoclonal antibody, we analyzed the expression of GM in 214 mature T-cell and NK-cell lymphomas. GM was preferentially expressed in nasal NK/T-cell lymphomas (100%), gamma delta T-cell lymphomas (100%), and intestinal T-cell lymphomas (85%). In contrast, GM expression was present at low prevalence in mycosis fungoides/Sézary syndrome (3%), anaplastic large-cell lymphoma (6%), panniculitis-like T-cell lymphoma (11%), and angioimmunoblastic T-cell lymphoma (0%) cases. Peripheral T-cell lymphomas of unspecified subtype showed an intermediate frequency (37%) of GM expression, consistent with their heterogeneous origin. We conclude that GM expression is a distinctive feature of the nasal NK/T-cell, gamma delta T-cell, and intestinal T-cell lymphomas, and suggest that these tumors develop from lymphocytes involved in innate immunity.

Shortened telomere length is demonstrated in T-cell subsets together with a pronounced increased telomerase activity in CD4 positive T cells from blood of patients with mycosis fungoides and parapsoriasis.

We have recently demonstrated that telomerase activity is increased and telomere length shortened in lymphocytes from peripheral blood of patients with cutaneous T-cell lymphoma. In order to determine which cell type has increased telomerase activity and shortened telomere length, CD4+, CD8+, CLA+ CD3+ and CLA- CD3+ T cells were isolated from peripheral blood of 25 patients, including 15 patients with mycosis fungoides and 10 patients with parapsoriasis. Eleven healthy individuals were used as controls; CD19+ B cells were separated from each individual as an internal control. The results showed that the increased telomerase activity was significantly predominating in the CD4+ T-cell subset. Significantly shortened telomere length was found in CD4+ and CD8+ T-cell subsets from the patients compared with the same cell subsets obtained from healthy individuals. However, no difference was observed between the subsets; CD19+ B cells collected from patients and healthy control individuals had similar telomerase activity and telomere length which was significantly different from the values found in T cells. The telomere length was significantly shorter in CLA+ CD3+ subset than in CLA- CD3+ subset. Interestingly, increased telomerase activity and shortened telomere length was also detected in CD4+ T cells from patients with parapsoriasis indicating that alteration of telomerase activity and telomere length in CD4+ T cells is an early event in the pathogenesis of cutaneous T-cell lymphoma. Thus, the results indicate that a significant high level of telomerase activity and shortened telomere length frequently occur in T cells of patients with CTCL and may reflect tumorigenesis.

Proteolytic activity of human lymphoid tumor cells. Correlation with tumor progression.

Matrix metalloproteinase (MMP) expression and production are associated with advanced-stage tumor and contribute to tumor progression, invasion and metastases. The current study was designed to determine the expression and production of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) by human lymphoid tumor cells. Changes in expression and production were also investigated during tumor progression of multiple myeloma and mycosis fungoides. In situ hybridization analysis revealed that lymphoblastic leukemia B cells (SB cell line), multiple myeloma (MM) cells (U266 cell line) and lymphoblastic leukemia T cells (CEM and Jurkat cell lines) express constitutively the mRNA for MMP-2 and/or MMP-9. We demonstrated by gelatin-zymography of cell culture medium that both enzymes were secreted in their cleaved (activated) form. In situ hybridization of bone marrow plasma cells and gelatin-zymography of the medium showed that patients with active MM (diagnosis, relapse, leukemic progression) express higher levels of MMP-2 mRNA and protein than patients with non-active MM (complete/objective response, plateau) and with monoclonal gammopathies of undetermined significance (MGUS). MMP-9 expression and secretion was similar in all patient groups. In patients with mycosis fungoides (MF), the expression of MMP-2 and MMP-9 mRNAs was significantly upregulated with advancing stage, in terms of lesions both positive for one of two mRNAs and with the greatest intensity of expression. Besides MF cells, the MMP-2 and/or MMP-9 mRNAs were expressed by some stromal cell populations (microvascular endothelial cells, fibroblasts, macrophages), suggesting that these cells cooperate in the process of tumor invasion. Our studies identify MMPs as an important class of proteinases involved in the extracellular matrix (ECM) degradation by human lymphoid tumors, and suggest that MMPs inhibitors may lead to important new treatment for their control.

Lck is involved in interleukin-2 induced proliferation but not cell survival in human T cells through a MAP kinase-independent pathway.

The role of Lck in IL-2-induced proliferation and cell survival is still controversial. Here, we show that the Src family kinase inhibitor, PP1, reduced the IL-2-induced proliferation of human T cells significantly without inhibiting the anti-apoptotic effect of IL-2. As Lck is the only Src family kinase activated upon IL-2 stimulation in T cells, this indicates that Lck is involved in IL-2-induced proliferation but not survival. IL-2-induced MAP kinase activation was only slightly inhibited by PP1, suggesting that Lck is not essential for IL-2-induced MAP kinase activation in human T cells. We found that an IL-2-sensitive, human mycosis fungoides-derived tumor T cell line is Lck negative, and that the IL-2-induced MAP kinase activation is comparable to non-cancerous T cells, although a little delayed in kinetics. An Lck expressing clone was established by transfecting Lck into mycosis fungoides tumor T cells, but Lck had no influence on the delayed kinetics of MAP kinase activation, indicating that Lck is not essential for MAP kinase activation in mycosis fungoides tumor T cells or in non-cancerous T cells. Taken together, this indicates that Lck is involved in IL-2-induced proliferation, but not cell survival, through a pathway not involving MAP kinase.

O6-alkylguanine-DNA alkyltransferase in cutaneous T-cell lymphoma: implications for treatment with alkylating agents.

Mycosis fungoides is a low-grade cutaneous T-cell lymphoma. Early treatment often involves the use of topical chemotherapy such as mechlorethamine or carmustine although single-agent oral chemotherapy with alkylators is common for advanced disease. Recently, in a Phase I study of the new alkylating agent temozolomide, two mycosis fungoides patients experienced a complete response. The mechanism of resistance to alkylating drugs such as temozolomide is thought to be due to the presence in tumor cells of the DNA repair protein, O6-alkylguanine-DNA alkyltransferase (AGT). The protein mediates a reaction with the O6-position of guanine in DNA, removing the lesion and leaving guanine intact. We, therefore, examined the levels of AGT in CD4+ T lymphocytes obtained by negative antibody selection from the blood of noncancerous individuals and mycosis fungoides patients, and in paraffin-embedded sections from mycosis fungoides patch, plaque, or tumor lesions and cells from involved lymph nodes. AGT protein levels were measured by quantitative immunofluorescence microscopy using a monoclonal antibody against human AGT. Using this approach, the mean level of our positive control (AGT-expressing cells) was 84,807 molecules/nucleus; values below 5,000 molecules/nucleus are considered very low. The mean AGT level in CD4+ T lymphocytes from noncancerous and cancerous individuals was 18,618 (n = 12) and 8,593 (n = 5), respectively. The mean fraction of outliers in circulating CD4+ T lymphocytes from mycosis fungoides patients was statistically significantly lower than T cells in lymph nodes. AGT molecules/nucleus from lymph node biopsies from 8 of 10 patients showed low (< 10,000 molecules/nucleus) or undetectable levels (n = 5) of AGT. The mean AGT level from samples of mycosis fungoides patch/plaque and tumor was also low at 221 (n = 4) and 2,363 (n = 6), respectively. Surprisingly, Hut78, a mycosis fungoides T-cell lymphoma cell line, was positive for AGT activity (median: 77,700 molecules/nucleus), and Hut102--another mycosis fungoides cell line--was low (median: 5,990 molecules/nucleus). Because AGT is a primary means of cell resistance to alkylating agents, the low level of AGT in neoplastic T lymphocytes from patients with mycosis fungoides suggests that treatment with alkylating agents producing O6-alkylguanine adducts, such as carmustine or temozolomide, may produce improved clinical outcomes.

Progression of mycosis fungoides is associated with changes in angiogenesis and expression of the matrix metalloproteinases 2 and 9.

Changes in angiogenesis and expression of extracellular matrix-degrading enzymes have been substantiated during progression of solid tumours, whereas information on haematological tumours remains circumstantial. In this study, 57 biopsies of mycosis fungoides (MF), a haematological tumour of T-cell lineage, were investigated immunohistochemically for the extent of angiogenesis, and by in situ hybridisation for the expression of matrix metalloproteinases 2 (MMP-2, collagenase A) and 9 (MMP-9, collagenase B). The biopsies we grouped according to the stage of progression: patch-->plaque-->nodular (most advanced). The extent of angiogenesis, as microvessel area, of MF lesions as a whole was significantly higher than that of normal uninjured skin, used as a control. When the stages of MF progression were compared, the values of MF patch stage overlapped that of control skin, while values were significantly higher in the plaque stage and even higher in the nodular stage. In these stages, microvessels were widely scattered in the tumour tissue, in close association with tumour cells, and they frequently displayed arborisation and microaneurysmatic dilation. In contrast, in the patch stage microvessels were irregularly distributed around the tumour aggregates, and arborisation or dilated structures were only rarely seen. The expression of MMP-2 and MMP-9 mRNAs underwent significant upregulation in relation to advancing stage. Indeed, the upstaging was significantly associated with higher proportions of lesions positive for each mRNA or for both, and with lesions with the greatest intensity of expression for each mRNA. Besides tumour cells, the MMP-2 mRNA was expressed by microvascular endothelial cells of intratumour and peri-tumour vessels, and by fibroblasts which were especially abundant in the stroma adjacent to the tumour nodules. The MMP-9 mRNA was found to be present in a subset of tissue macrophages which were more frequently located in close vicinity to the tumour nodules. In contrast, in control skin, a weak positivity for the MMP-2 mRNA in very few microvascular endothelial cells and no signal for the MMP-9 mRNA were observed. These in situ data suggest that angiogenesis and degradation of the extracellular matrix occur simultaneously during MF progression. They imply that interaction between tumour cells and their microvasculature are all the more likely to occur during progression, occasionally with the contribution of tumour-associated stromal cells.