Matrix metalloproteinase‐7 activates heparin‐binding epidermal growth factor‐like growth factor in cutaneous squamous cell carcinoma

Background Tumour‐specific expression of matrix metalloproteinase (MMP)‐7 has been noted in cutaneous squamous cell carcinomas (SCCs) in patients with recessive dystrophic epidermolysis bullosa (RDEB). Objectives To examine the potential role of MMP‐7 in shedding of heparin‐binding epidermal growth factor‐like growth factor (HB‐EGF) in RDEB‐associated and sporadic SCCs. Methods Tissue microarrays of RDEB‐associated SCC (n = 20), non‐EB SCC (n = 60) and Bowen disease (n = 28) were immunostained for MMP‐7, CD44 variant 3 (CD44v3) and HB‐EGF. Shedding of HB‐EGF was studied in vitro using two cutaneous SCC cell lines. Results Immunohistochemical analysis showed that HB‐EGF was absent in tumour cells when MMP‐7 and CD44v3 colocalized, and that the absence of HB‐EGF was more pronounced in RDEB‐associated SCCs than in non‐EB SCCs. The loss of HB‐EGF in MMP‐7–CD44v3 double‐positive areas was interpreted to indicate shedding and activation of HB‐EGF; this was also detected in Bowen disease indicating its importance in the early phase of SCC development. Specific knockdown of MMP‐7 expression in human cutaneous SCC cells by small interfering RNA inhibited shedding of HB‐EGF and resulted in diminished activation of the EGF receptor (EGFR) and ERK1/2, and in reduced proliferation of SCC cells. Conclusions These findings provide evidence for the role of MMP‐7 in promoting the growth of cutaneous SCCs by shedding HB‐EGF, and identify EGFR signalling as a potential therapeutic target in RDEB‐associated SCC and unresectable sporadic cutaneous SCC.     

Effective induction of melanoma‐antigen‐specific CD8+ T cells via Vγ9γδT cell expansion by CD56high+ Interferon‐α‐induced dendritic cells

Dendritic cells (DCs) can be differentiated from CD14⁺ monocytes in the presence of interferon‐α (IFNα) and granulocyte/macrophage‐colony stimulating factor (GM‐CSF) in vitro and are known as IFN‐DCs. Circulating blood CD56⁺ cells expressing high levels of CD14, HLA‐DR and CD86 have been shown to spontaneously differentiate into DC‐like cells in vitro after their isolation from blood. We show here that IFN‐DCs expressing high levels of CD56 (hereafter, CD56^high+ IFN‐DCs) can be differentiated in vitro from monocytes obtained as adherent cells from healthy donors and patients with metastatic melanoma. These cells expressed high levels of CD14, HLA‐DR and CD86 and possessed many pseudopodia. These CD56^high+ IFN‐DCs may be an in vitro counterpart of the circulating CD56⁺ CD14⁺ CD86⁺ HLA‐DR⁺ cells in blood. Conventional mature DCs differentiated from monocytes as adherent cells in the presence of GM‐CSF, IL‐4 and TNF‐α (hereafter, mIL‐4DCs) did not express CD56 or CD14. In contrast to mIL‐4DCs, the CD56^high+ IFN‐DCs exhibited a stronger capacity to stimulate autologous CD56⁺ Vγ9γδT cells highly producing IFNγ in the presence of zoledronate and IL‐2. The CD56^high+ IFN‐DCs possessing HLA‐A*0201 effectively induced Mart‐1‐modified melanoma peptide (A27L)‐specific CD8⁺ T cells through preferential expansion of CD56⁺ Vγ9γδT cells in the presence of A27L, zoledronate and IL‐2. Vaccination with CD56^high+ IFN‐DCs copulsed with tumor antigens and zoledronate may orchestrate the induction of various CD56⁺ immune cells possessing high effector functions, resulting in strong immunological responses against tumor cells. This study may be relevant to the design of future clinical trials of CD56^high+ IFN‐DCs‐based immunotherapies for patients with melanoma.     

Impaired T‐cell‐dependent protection against Leishmania major infection in HIV‐positive patients is associated with worsened disease outcome

Cutaneous leishmaniasis (CL) patients coinfected with HIV are known to show a more severe, prolonged course of disease; the immunological basis is not known. We now assessed clinical features, sera and skin biopsies of HIV⁺ and HIV^? patients with CL to identify drivers of increased susceptibility to Leishmania. CL lesion numbers, surface, and healing duration were significantly increased in HIV⁺ as compared to HIV^? patients (2.5, 14 and >4‐fold, respectively). Patients with HIV infection exhibited lower serum Leishmania‐specific IgG levels and decreased IL‐6 and IL‐8. Most importantly, dramatically decreased numbers of CD4⁺ T cells (approximately eightfold), but not CD8⁺ cells, together with fewer CXCR3⁺ Th1 cells, fewer Foxp3⁺ effector/regulatory T cells, and reduced levels of IFN‐γ expression were found in lesional skin. Our findings suggest that compromised CD4⁺ T‐cell responses may be responsible for worsened disease outcome leading to defects in parasite elimination in the absence of sufficient numbers of IFN‐γ‐producing Th1 cells.     

Photodynamic therapy with BF‐200 ALA for the treatment of actinic keratosis: results of a prospective,randomized, double‐blind,placebo‐controlled phase III study

Background Photodynamic therapy (PDT) with 5‐aminolaevulinic acid (ALA) provides a therapeutic option for the treatment of actinic keratosis (AK). Different strategies are applied to overcome the chemical instability of ALA in solution and to improve skin penetration. A new stable nanoemulsion‐based ALA formulation, BF‐200 ALA, is currently in clinical development for PDT of AK. Objectives To evaluate the efficacy and safety of PDT of AK with BF‐200 ALA. Methods The study was performed as a randomized, multicentre, double‐blind, placebo‐controlled, interindividual, two‐armed trial with BF‐200 ALA and placebo. A total of 122 patients with four to eight mild to moderate AK lesions on the face and/or the bald scalp were included in eight German study centres. The efficacy of BF‐200 ALA after one and two PDT treatments was evaluated. BF‐200 ALA was used in combination with two different light sources under illumination conditions defined by European competent authorities. Results PDT with BF‐200 ALA was superior to placebo PDT with respect to patient complete clearance rate (per‐protocol group: 64% vs. 11%; P < 0·0001) and lesion complete clearance rate (per‐protocol group: 81% vs. 22%) after the last PDT treatment. Statistically significant differences in the patient and lesion complete clearance rates and adverse effect profiles were observed for the two light sources, Aktilite^® CL128 and PhotoDyn^® 750, at both time points of assessment. The patient and lesion complete clearance rates after illumination with the Aktilite^® CL128 were 96% and 99%, respectively. Conclusions BF‐200 ALA is a very effective new formulation for the treatment of AK with PDT. Marked differences between the efficacies and adverse effects were observed for the different light sources used. Thus, PDT efficacy is dependent both on the drug and on the characteristics of the light source and the illumination conditions used.     

Photodynamic therapy with topical methyl‐ and hexylaminolevulinate for prophylaxis and treatment of UV‐induced SCC in hairless mice

Please cite this paper as: Photodynamic therapy with topical methyl‐ and hexylaminolevulinate for prophylaxis and treatment of UV‐induced SCC in hairless mice. Experimental Dermatology 2010; 19 : e166–e172. Abstract Background: Hexyl aminolevulinate (HAL) is a long‐chained 5‐aminolevulinic acid‐ester that has been proposed as a novel photosensitizing agent to methyl aminolevulinate (MAL) in topical photodynamic therapy (PDT). The more lipophilic HAL, may improve treatment outcome for non‐melanoma skin cancer. Objective: To compare the prophylactic and therapeutic effects of HAL‐ and MAL‐PDT for ultraviolet‐induced squamous cell carcinomas (SCCs) in hairless mice. Methods: Mice (n = 249) were irradiated with solar UV‐radiation (UVR) until SCC occurred. Before any skin changes developed, two prophylactic PDT treatments were given, using creams of HAL (2%, 6%, 20%) or MAL (20%) followed by illumination (632 nm, Aktilite, Photocure). Two therapeutic PDT‐treatments were given by randomization to the first developed SCC of 1 mm. Primary end‐points were time to first SCC of 1 mm and complete SCC clearance. Secondary end‐points were time to SCC‐recurrence, PpIX fluorescence and skin reactions to PDT. Results: The median time to first SCC was significantly longer for mice treated with prophylactic HAL‐PDT (2%, 6% and 20% HAL, 264 days) and MAL‐PDT (20% MAL, 269 days) than mice exposed to UVR (186 days) and UVR + placebo‐PDT (199 days) (P < 0.0001). The therapeutic efficacy of HAL‐ and MAL‐PDT showed cure rates of 23–61.5% (P = 0.11). Similar PpIX fluorescence intensity and severity of clinical reactions were seen for HAL‐ and MAL‐groups, although mice developed more intense hyper‐pigmentation when treated with 20% MAL‐PDT compared with 2% HAL‐PDT. Conclusions: PDT with HAL (2%, 6% and 20%) and MAL (20%) is equally effective to prevent and treat UV‐induced SCC in hairless mice.     

Evidence that regression in Keratoacanthoma is immunologically mediated: a comparison with squamous cell carcinoma

Recent research observations suggest that the keratoacanthoma (KA) is a form of resolving squamous cell carcinoma (SCC). The mechanism by which this resolution takes place has not been fully explored, although it may have an immunological basis. To investigate this, we compared 15 clinically and histologically diagnosed KAs and 15 SCCs with regard to cellular infiltrate and keratin expression. We found that KAs have significantly higher numbers of CD3⁺ and CD4⁺ cells invading their epidermal component than SCCs. The lymphocytes infiltrating KAs were more immunologically active, as greater numbers expressed the interleukin-2 receptor (IL-2R) than those in SCCs. It is of interest that CD36 was expressed by a significantly greater proportion of tumour cells within KAs than SCCs. This was also the case for the intercellular adhesion molecule ICAM-1, and the differentiation marker keratin 10. Overall, these findings suggest that KA regression is immunologically mediated, with activated (IL-2R⁺) CD4⁺ T lymphocytes and adhesion molecules playing a pivotal role in the immune response.     

Photodynamic therapy with 5‐aminolevulinic acid in actinic cheilitis: an 18‐month clinical and histological follow‐up

Background Actinic cheilitis (AC) may bear the initial and superficial changes of actinically induced squamous cell carcinoma (SCC) and may progress into fully developed SCCs. Early and effective treatment is important. Objective To assess the clinical and histological long‐term outcome in AC after two ALA‐PDT sessions. Methods Patients with histologically proven grade 1 and 2 AC received two ALA‐PDT sessions at 2 weeks interval. Subjects with complete clinical response at 3 months were evaluated further clinically and histologically at months 6, 12 and 18. Long‐term study outcome was defined as clinical and histological AC recurrence among patients with complete clinical response 3 months after treatment. Cosmetic outcome was assessed by the investigators at the final follow‐up visit at 18 months. Results Of the 40 patients enrolled, 38 completed the study. Complete clinical response at 3 months was achieved in 26 patients. At 6 months, clinical and histological recurrence occurred in three patients and at 12 months, one more patient showed clinical and histological recurrence. At 18 months, overall clinical recurrence rate was 15.38% (4/26), while overall histological recurrence rate was 34.61% (9/26). Cosmetic outcome was rated as excellent in more than 80% of evaluated cases. Conclusion PDT represents a moderately effective treatment modality in AC. Optimization of treatment procedure and protocols is still needed for higher response rates to be achieved. Moreover, the high treatment cost should be given consideration. Further long‐term follow‐up studies are needed for assessment of clinical and histological very late recurrences that could be expected after PDT.     

Papuloerythroderma‐like cutaneous involvement of a CD62L− subclone of T‐cell prolymphocytic leukemia

We report the case of an 88‐year‐old Japanese man with erythrodermic involvement of T‐cell prolymphocytic leukemia (T‐PLL). He had a history of pharyngeal diffuse large B‐cell lymphoma successfully treated with polychemotherapy including cyclophosphamide and epirubicin, 6 years before the current illness. He presented with numerous reddish, coalescing, flat‐topped papules on the trunk and extremities, sparing the skin folds of the abdomen, the features of which mimicked those of papuloerythroderma. Immunohistochemistry showed perivascular and epidermotropic infiltration of CD3⁺ CD4⁺ T cells in the cutaneous lesion. However, flow cytometric analysis revealed that the skin infiltrating T cells were negative for surface CD4, and that CD3⁺ CD4^? CD8^? cells made up 92% of the T‐cell fraction of peripheral blood. The circulating atypical T cells had a round or oval nucleus and prominent nucleoli, and the deletion of chromosomes 6q, 13 and 17. These cytological profiles were consistent with those of T‐PLL and distinct from those of Sézary cells. The same T‐cell clone was detected in the cutaneous lesion and peripheral blood, but the expression of CD62L was absent in the skin infiltrates and present in the circulating cells. No specific mutation was detected in STAT3 or STAT5B. Although low‐dose oral etoposide had a beneficial effect on the skin rash, a fatal crisis of marked leukocytosis (169 × 10³/μL) occurred 19 months after the illness onset. CD62L‐leukemic cells of T‐PLL may infiltrate the skin to form papuloerythroderma‐like cutaneous lesions.     

Long‐term follow‐up of photodynamic therapy with a self‐adhesive 5‐aminolaevulinic acid patch: 12 months data

Background Photodynamic therapy with a self‐adhesive 5‐aminolaevulinic acid (5‐ALA) patch shows high efficacy rates in the treatment of mild to moderate actinic keratosis (AK) in short term trials. Objectives The purpose of the trial was to follow up patients after successful 5‐ALA patch‐PDT at 3 month intervals over a total period of 12 months. Patients who had received placebo‐PDT or cryosurgery served for comparison. Patients/methods Three months after therapy, 360 patients from two separate randomized parallel group phase III studies (one superiority trial vs. placebo‐PDT, one noninferiority trial vs. cryosurgery) were suitable for the follow‐up study. Patients had to show at least one successfully treated AK lesion after initial therapy. A total of 316 patients completed the follow‐up. Results Twelve months after a single treatment, 5‐ALA patch‐PDT still proved superior to placebo‐PDT and cryosurgery (P < 0·001 for all tests). On a lesion basis, efficacy rates were 63% and 79% for PDT, 63% for cryosurgery and 9% and 25% for placebo‐PDT. Recurrence rates of patch‐PDT proved superior to those of cryosurgery (per protocol set: P = 0·011, full analysis set: P = 0·049). While 31% of cryosurgery lesions were still hypopigmented after 1 year, the 5‐ALA patch‐PDT groups showed hypopigmentation in 0% (superiority trial) and 3% (noninferiority trial) of the treated lesions. Conclusion Twelve months after a single 5‐ALA patch‐PDT the majority of lesions were still cleared with an excellent cosmetic outcome. 5‐ALA patch‐PDT proved to be superior to cryosurgery in the noninferiority study setting.     

Single vs. fractionated photodynamic therapy for face and scalp actinic keratoses: a randomized,intraindividual comparison trial with 12‐month follow‐up

Objective To compare the efficacy and tolerability of a single ALA‐PDT illumination scheme with that of a fractionated ALA‐PDT illumination scheme in face and scalp actinic keratoses (AKs). Methods Eligible patients received either a single ALA‐PDT illumination or a fractionated illumination scheme randomly allocated to alternate sides of face/scalp. The side allocated to a single illumination received 75 J/cm². This side received 2 sessions performed 7 days apart. Lesions on the fractionated illumination scheme side received 20 and 80 J/cm², 4 and 6 hours after a single ALA application. Patients were evaluated at baseline, at 3 and 12 months after treatment. Efficacy end point included the individual AK lesion clearance rate. Results Thirty three patients with 266 lesions were enrolled in the study. Three months after treatment the overall lesion complete response rate was 89.05% for the single scheme and 96.12% for the fractionation scheme while at the 12‐months follow‐up response rate decreased to 85.4% for the single illumination and to 93.79% for the fractionated illumination group. Looking at lesion response based on lesion grade fractionated photodynamic therapy (PDT) resulted in larger rates of cured grade I as well as grade II lesions. Recorded adverse events were transient and did not demand additional therapy. Conclusions Our results demonstrate that higher responses are achieved with fractionated PDT compared with single illumination PDT. The study data indicate that fewer treatment sessions may be needed with fractionated PDT increasing that way the comfort of the patient regarding number of visits, treatment cost and treatment‐related downtime.     

Topical photodynamic therapy is immunosuppressive in humans

Background Visible light irradiation after application of a photosensitizer (topical photodynamic therapy; PDT) is increasingly used to treat nonmelanoma skin cancers and premalignant actinic keratoses. PDT can provide a cosmetically superior alternative to surgery, but carries failure rates of 10–40%. While some murine studies have suggested immune enhancement by PDT, others reported immunosuppressive effects, which may indicate impaired antitumour immunity and thus compromised tumour clearance. Objectives This study aimed to determine the in vivo immune effects of PDT in humans. Methods Using healthy, Mantoux‐positive volunteers, we irradiated discrete areas of the back with narrowband red light (630 nm; 37 J cm^?2), with and without prior application of 5‐aminolaevulinic acid (ALA) or methyl aminolaevulinate (MAL). Adjacent, untreated areas served as immunologically intact control sites. Delayed‐type hypersensitivity responses to tuberculin purified protein derivative (Mantoux reactions) were then elicited in each of the irradiated, unirradiated and control sites, and the intensity of the reactions was quantitated with an erythema meter and by measurement of Mantoux diameter. By comparing Mantoux intensity at treated and control sites, immunosuppression was determined in each volunteer for each intervention. Results We found that both MAL‐PDT and ALA‐PDT significantly suppressed Mantoux erythema (by 30% and 50%, respectively) and diameter (41% and 38%). Red light alone significantly suppressed diameter (22%) but not erythema (13%). Conclusions Topical PDT induced significant immune suppression, which could impair local antitumour immune responses and may thus contribute to treatment failure.     

Vaccination with photodynamic therapy-treated macrophages induces highly suppressive T-regulatory cells

Background/purpose: The present study explores whether photodynamic therapy (PDT)‐induced apoptosis can increase the number of tolerogenic regulatory T cells (Treg) and limit collateral tissue damage. Methods: BALB/c mice were vaccinated subcutaneously three times with PDT‐induced apoptotic or thaw‐frozen, necrotic non‐infected autologous macrophages (MΦ). Two weeks after the last vaccination, mice were infected intradermally with 10⁶ promastigotes of Leishmania major. Results: Mice that received PDT‐induced apoptotic MΦ had fewer parasites and higher numbers of Treg than mice vaccinated with thaw‐frozen necrotic MΦ or phosphate‐buffered saline (PBS). Interleukin (IL)‐4 and IL‐6 were significantly suppressed, while IL‐10 was increased in mice that received the PDT‐induced apoptotic MΦ. The role of Treg in this process was confirmed through Treg transfer from vaccinated to naïve mice. Mice receiving CD4⁺CD25⁺ cells from mice vaccinated with PDT‐induced apoptotic MΦ showed smaller lesions 3 weeks after infection and lower parasitic burdens than mice that received Tregs from mice of thaw‐frozen necrotic MΦ or PBS groups. These changes were mediated by the depletion of CD3⁺CD8⁺ and NKT cells and increased levels of IL‐12p70 and interferon‐γ, IL‐10, and TGF‐β in the cutaneous leishmaniasis lesions. Conclusion: Vaccination with apoptotic MΦ‐induced tolerogenic Treg cells that limited collateral tissue damage and diminished parasitic burden.     

Prospective study of topical 5‐aminolevulinic acid photodynamic therapy for the treatment of severe adolescent acne in Chinese patients

Acne vulgaris is one of the most common skin diseases in adolescents. In the present study, we aimed to evaluate the effectiveness and safety of topical 5‐aminolevulinic acid (ALA)‐mediated photodynamic therapy (PDT) for the treatment of severe acne in Chinese adolescent patients. Twenty‐one Chinese adolescent patients aged 12–18 years with Pillsbury III–IV severe facial acne were treated with three courses of ALA‐PDT. A 5% ALA lotion was applied topically for 60 min followed by irradiation with light‐emitting diode light at 633 nm with a light intensity of 75–80 mW/cm² and a light dose of 90–96 J/cm². Clinical assessment was conducted before and after each treatment, and at each follow‐up session. The total effective rates were 85.71%, 90.48%, and 95.23% after the three PDT sessions, and at the 4‐ and 8‐week follow ups, respectively. ALA‐PDT is an effective treatment for severe adolescent acne vulgaris, and is associated with mild and reversible side‐effects.     

Cutaneous Penicillium marneffei infection in a patient with idiopathic CD4+ lymphocytopenia

We describe a case of cutaneous Penicillium marneffei infection in a non‐HIV‐infected male patient with idiopathic CD4⁺ T lymphocytopenia (ICL). The cutaneous lesions were cured after the treatment of itraconazole combined with interleukin‐2.     

MMP‐10 (Stromelysin‐2) and MMP‐21 in human and murine squamous cell cancer

Abstract: The squamous cell cancers (SCC) of renal transplant recipients are more aggressive and metastasize earlier than those of the non‐immunocompromised population. Matrix metalloproteinases (MMPs) have a central role in tumor initiation, invasion and metastasis. Our aim was to compare the expression of MMPs‐10, ‐12 and ‐21 in SCCs from immunosuppressed (IS) and control patients and the contribution of MMPs‐10 and ‐21 to SCC development in the FVB/N‐Tg(KRT5‐Nfkbia)3Rto mouse line. Immunohistochemical analysis of 25 matched pairs of SCCs, nine of Bowen’s disease and timed back skin biopsies of mice with selective inhibition of Rel/NF‐κB signalling were performed. Semiquantitatively assessed stromal MMP‐10 expression was higher (P = 0.009) in the control group when compared with IS patients. Tumor cell‐derived MMP‐10, ‐12 and ‐21 expression did not differ between the groups but stromal fibroblasts of the control SCCs tended to express MMP‐21 more abundantly. MMP‐10 expression was observed already in Bowen’s disease while MMP‐21 was absent. MMP‐10 and ‐21 were present in inflammatory or stromal cells in ageing mice while dysplastic keratinocytes and invasive cancer were negative. Our results suggest that MMP‐10 may be important in the initial stages of SCC progression and induced in the stroma relating to the general host‐response reaction to skin cancer. MMP‐21 does not associate with invasion of SCC but may be involved in keratinocyte differentiation.     

Spindle‐cell variant of primary cutaneous follicle center lymphoma spreading to the hepatobiliary tree,mimicking Klatskin tumor

Primary cutaneous follicle center lymphoma (pcFCL) is an indolent type of primary cutaneous B‐cell lymphoma (pcBCL) rarely disseminating to other organs. PcBCL with spindle‐cell morphology has been described as a rare variant of pcFCL but the prognosis data of this variant is sparse. We report a rare case of spindle‐cell pcFCL with CD20⁺, CD79a⁺, CD3⁺, Bcl‐6⁺, Mum‐1^? and CD10^?tumor cells that infiltrated the hepatic hilum, mimicking a Klatskin tumor. On the basis of the sparse published data on spindle‐cell morphology of pcBCL, this growth pattern should elicit awareness of an increased risk of systemic involvement in the otherwise indolent pcFCL.     

Multiple cutaneous reticulohistiocytosis with T‐cell large granular lymphocyte clonopathy

A 63‐year‐old Caucasian man presented with a 4‐month history of disseminated asymptomatic reddish‐brown papulonodular lesions. A skin biopsy showed dermal infiltration with CD68⁺ histiocytes, predominantly with eosinophilic cytoplasm, some with a ground‐glass cytoplasm, and a small number of giant cells. The diagnosis of multiple cutaneous reticulohistiocytosis was made. Bone marrow immunophenotyping due to peripheral blood lymphocytosis revealed the presence of a monoclonal population of CD3⁺, CD8⁺ CD57⁺ large granular lymphocytes. The present case suggests the coexistence of multiple cutaneous reticulohistiocytosis with an underlying disorder.     

Expression of Fas and Fas ligand in primary cutaneous squamous cell carcinoma in association with grade of tumor differentiation

Background The aim of this study was to evaluate whether Fas (CD95) and Fas ligand (FasL) immunoreactivity in cutaneous squamous cell carcinoma (SCC) are correlated with grade of tumor differentiation. Methods A total of 31 cutaneous SCC specimens excised during 1997–2004 were collected from the four branch hospitals of the Catholic University of Korea. A tissue microarray technique was used for immunohistochemical staining. Expression of Fas and FasL was evaluated in correlation with the grade of tumor differentiation. Statistical analysis was performed using Fisher’s exact test and exact trend test. Results Six of 31 SCCs exhibited strong (+++) intensity for Fas immunostaining, and all of these were well differentiated. Five of 31 SCCs exhibited strong (+++) intensity for FasL staining; all of these were moderately or poorly differentiated. Conclusions Fas was expressed more strongly in well‐differentiated SCCs than in poorly differentiated tumors. FasL was expressed more strongly in moderately and poorly differentiated tumors. These findings indicate that Fas and FasL play important roles in immune surveillance and grade of differentiation in SCC.