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Background: Malignant melanoma (MM) often shows multiple chemo-resistance, leading to poor prognosis of the patients. Therapeutic anti-cancer vaccination may be a feasible way to prolong the survival of patients. We have demonstrated that application of antigenic peptides via the tape-stripped, horny layer-removed skin, known as percutaneous peptide immunization (PPI), induces tumor cell-specific cytotoxic T lymphocytes (CTLs) in rodents and humans., Objective: To evaluate clinical significance of PPI in advanced MM patients., Methods: We performed PPI in 59 patients undergoing advanced MM with Melan-A, tyrosinase, MAGE-2, MAGE-3 and gp-100 peptides based on HLA typing in individuals. The induction of CTLs was assessed by the tetramer or pentamer flow cytometry in 35 patients. Patients showing positive CTL responses to all antigens were defined as complete responder (n=18), and those showing negative responses to at least one applied antigen were classified as incomplete responder (n=17). The primary endpoint of the study was overall survival (OS). For statistical analysis, log-rank test, univariate and multivariate Cox proportional hazard model were used., Results: OS of the complete responders was longer than that of the incomplete responders (median survival time: 55.8 vs 20.3 months, log rank P=0.089). A hazard ratio for the complete responders relative to the incomplete responders was 0.23 (95% confidence interval: 0.06-0.93, P=0.039) in a multivariate Cox proportional hazard model., Conclusion: The induction of CTLs was a novel independent survival factor, and the induction of peptide-specific CTLs by PPI contributes to the prolonged survival and represents an impact on therapeutic approaches in MM. Unique trial number: UMIN000005706., (Copyright © 2014 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.)

A 66-year-old man was admitted to our hospital presenting 2 weeks' history of fever of unknown origin with elevated levels of lactate dehydrogenase and C-reactive protein. Six years before this episode, he had developed diffuse large B-cell lymphoma, which had been successfully treated with chemoradiation. While recurrence of diffuse large B-cell lymphoma was suspected, there was neither lymphadenopathy nor tumor formation by the imaging study. Random biopsy from normal-appearing abdominal skin showed extensive infiltration of CD20(+), CD79a(+), CD3(-) atypical lymphoid cells in the lumen of vessels in subcutaneous tissues. These findings led us to the diagnosis of intravascular B-cell lymphoma. Following rituximab plus cyclophosphamide, adriamycin, vincristine and prednisolone therapy, high fever subsided, and lactate dehydrogenase and C-reactive protein levels returned to the normal range. In conclusion, random skin biopsy is useful for the early diagnosis of intravascular B-cell lymphoma., (© 2010 Japanese Dermatological Association.)

Primary cutaneous aggressive epidermotropic CD8(+) T-cell lymphoma (CD8(+)TCL) is an extremely rare entity with distinct clinicopathological features. While the CD15 antigen is typically associated with classic Hodgkin's lymphoma, aggressive peripheral T-cell lymphomas, including advanced stage cutaneous T-cell lymphomas, rarely express this molecule. We report a case of primary cutaneous aggressive epidermotropic CD8(+)TCL, in which lymphoma cells are CD15(+)CD30(-) with a medium-to-large pleomorphic phenotype. Although the functional characteristics of CD15 expression in the cutaneous lymphomas are not fully understood, the poor prognosis of primary cutaneous aggressive epidermotropic CD8(+)TCL might be associated with the presence of this molecule in our case.

POLH mutations were identified in 16 Japanese patients, who were diagnosed, both clinically and at a cellular level, as being of the xeroderma pigmentosum variant type (XPV). While all the patients developed skin cancer with an average onset of the cancer at 45 years, in non-XP Japanese the onset was at over 70 years. All the cell strains from the patients were normal or slightly hypersensitive to UV and most of these showed enhanced UV sensitivity when the post-UV colony formation was performed in the presence of caffeine. Immunoprecipitation analysis with two kinds of anti-POLH protein antibodies revealed that cells from 13 patients did not show the 83 kDa POLH band and that cells from one patient had a faint 83 kDa band. All of these 14 cell strains, without a POLH band or with a weak POLH band, had mutations in the POLH gene. The IP analysis of the POLH protein revealed a very useful method for screening the patients suspected of XPV. Seven mutations in the POLH gene including three novel mutations were identified. Among the mutations detected, 11 alleles out of 28 (39%) were G490T mutations.

Interactions between chemokines and chemokine receptors are involved in migration and invasion of lymphoma cells. We investigated expression profiles of CXCR3 and CCR4 by immunohistochemistry and flow cytometry, and their biologic behaviors by real-time horizontal chemotaxis assay in cutaneous T cell and NK/T-cell lymphomas (TCLs). Tumor cells in mycosis fungoides (MF) constantly expressed CXCR3 at the patch stage, and expressed CCR4 at the tumor stage and in the folliculotropic variant of MF. Neoplastic cells at the plaque stage expressed CXCR3 and/or CCR4. Sezary cells in the dermis and circulation were positive for CCR4. Epidermotropic atypical cells in pagetoid reticulosis expressed CXCR3. CD30 cells exclusively expressed CCR4 in anaplastic large-cell lymphoma, and CXCR3 and/or CCR4 in lymphomatoid papulosis. In CD8TCL and extranodal NK/TCL characterized by extensive epidermotropism, tumor cells were positive for CXCR3. These data demonstrated preferential expression of CXCR3 in epidermotropic tumor cells, and of CCR4 in dermis-based lymphomas. In chemotaxis assays, CCR4 tumor cells in MF and CXCR3 tumor cells in CD8TCL migrated to thymus and activation-regulated chemokine and inducible protein-10, respectively. Therefore, spatial and temporal interactions between chemokine receptors and their ligands seem to dictate recruitment and retention of lymphoma cells in the skin.

This editorial review summarizes the results of 5 meetings sponsored by the International Society for Cutaneous Lymphoma at which the clinicopathologic and ancillary features of early mycosis fungoides were critically examined. Based on this analysis, an algorithm was developed for the diagnosis of early mycosis fungoides involving a holistic integration of clinical, histopathologic, immunopathologic, and molecular biological characteristics. A novel aspect of this algorithm is that it relies on multiple types of criteria rather than just one, for example, histopathology. Before its finalization, the proposed diagnostic algorithm will require validation and possibly further refinement at multiple centers during the next several years. It is anticipated that a more standardized approach to the diagnosis of early mycosis fungoides will have a beneficial impact on the epidemiology, prognostication, treatment, and analysis of clinical trials pertaining to this most common type of cutaneous lymphoma.

We demonstrated that percutaneous peptide immunization by way of skin with impaired barrier function is a simple and noninvasive strategy to generate effective immune responses against tumors. This therapeutic strategy seems to be beneficial for the treatment of skin-associated malignancies, including CTCL, because specific CTLs are considered to be well-induced in lymph nodes that neighbor barrier-disrupted skin (Fig. 3). There remain unsolved issues concerning (1) the ability of cytokines and growth factors to enhance efficacy of this therapy and (2) the time schedule of clinical trials. It was recently shown that application of antigenic protein or its coding DNA to skin with increased permeability yields antigen-specific antibody responses. Because the skin represents an easily accessible site for immunization and vaccination, percutaneous immunization using corneum barrier-disrupted skin is an alternative to injection of CTL-inducing molecules and can readily be exploited for cancer treatment in humans. The effective induction of CTLs suggests that the method that uses barrier-disrupted skin can potentially be applied to treatments of virus and helminth infections with the use of certain antigenic peptides.

Adult T cell leukemia/lymphoma (ATL) is a malignancy of CD4+ T cells that is endemic in certain areas in Japan. Two types of cutaneous ATL thought to originate from skin include cutaneous tumor and erythematopapule types. Patients with cutaneous ATL show neither leukemic involvement nor invasion of tumor cells into the lymph nodes for at least six months. The differential diagnosis between cutaneous ATL and mycosis fungoides is often difficult. The presence of monoclonal integration of human T lymphotropic virus-I proviral DNA in skin samples is of definitive diagnostic value in cutaneous ATL.

Two conferences were sponsored by the International Society for Cutaneous Lymphomas (ISCL) to gain consensus on definitions and terminology for clinical use in erythrodermic cutaneous T-cell lymphoma (E-CTCL). Three subsets of E-CTCL were defined: Sézary syndrome ("leukemic phase" E-CTCL), erythrodermic mycosis fungoides (secondary E-CTCL that develops in patients with mycosis fungoides), and E-CTCL, not otherwise defined. The hematologic criteria recommended for Sézary syndrome are intended to identify patients with a worse prognosis compared with the other E-CTCL subsets and consist of one or more of the following: (1) an absolute Sézary cell count of 1000 cells/mm3 or more; (2) a CD4/CD8 ratio of 10 or higher caused by an increase in circulating T cells and/or an aberrant loss or expression of pan-T cell markers by flow cytometry; (3) increased lymphocyte counts with evidence of a T-cell clone in the blood by the Southern blot or polymerase chain reaction technique; or (4) a chromosomally abnormal T-cell clone. For staging purposes, it is proposed that these criteria define the B2 blood rating and that the B2 rating be considered equivalent to nodal involvement.

Treatment with 8-methoxypsoralen (8-MOP) and ultraviolet A light (UVA) has been reported to modulate cytokine production in various cells. Our study was conducted to see the effects of 8-MOP/UVA on the expression/production of cytokines in peripheral blood lymphocytes and monocytes in relation to the therapeutic mechanisms of extracorporeal photochemotherapy. 8-MOP/UVA augmented the expression of mRNAs for interferon-gamma (IFN-gamma) and interleukin (IL)-2 and reduced those for IL-4 and IL-10 in peripheral blood mononuclear cells (PBMCs) from normal subjects and Sézary syndrome patients. This enhancement of Th1 cytokines was caused by increment of cytokine production by Th1 cells but not by conversion of Th2 cells to produce Th1 cytokines. The number of IFN-gamma-secreting lymphocytes was markedly increased in 8-MOP/UVA-treated PBMCs 20 h after treatment, and its amount was elevated in culture supernatants. However, this enhanced production of IFN-gamma was found only until three days after 8-MOP phototreatment, and its level was rapidly declined by five days after treatment. In addition to this Th1-polarized action, 8-MOP/UVA-treated PBMCs produced enhanced amounts of IL-8 upon stimulation with anti-CD3/CD28 antibodies. Phototreated CD4+ but not CD8+ cells provided excellent T cell help for monocytes to produce IL-8 via a direct cell-to-cell contact mechanism. These findings suggest that 8-MOP/UVA has a transient but biologically active Th1-skewing action in T cells, and the phototreated T cells simultaneously stimulate monocytes to produce IL-8. It is suggested that 8-MOP/UVA exerts a beneficial therapeutic effect on malignant Th2 neoplasms as a Th1-skewing cytokine modifier and that 8-MOP-phototreated CD4+ T cells allow monocytes to become effective tumor antigen-presenting cells for tumor-specific cytotoxic T cells.

As typically represented by Sézary syndrome, the leukemic form of cutaneous T-cell lymphoma (CTCL) mostly exhibits erythroderma. A patient with CTCL had slowly developing skin tumors as well as chronic leukemia. The tumor cell was CD4+ CD7- Th2 cells lacking T-cell receptor/CD3 complex and persistently occupied 27% to 48% of peripheral blood lymphocytes. In skin tumors, only 13% of tumor-infiltrating lymphocytes were malignant cells and substantial numbers of nonmalignant CD4+ or CD8+ T cells and B cells coinfiltrated. CD8+-infiltrating T cells had cytotoxic activity against the malignant T cell. Our case demonstrates the existence of the leukemic form of CTCL presenting with skin manifestation other than erythroderma and parapsoriatic patches. The nonerythrodermic feature and indolent course may be associated with the lack of T-cell receptor/CD3 expression and coinfiltration of a high percentage of nontumor lymphocytes, including tumoricidal CD8+ T cells.

Sézary syndrome (SzS) is the leukaemic variant of cutaneous T cell lymphoma (CTCL), whose malignant T cells are of the Th2 type in most cases. In this study we investigated the tumouricidal activity of cytotoxic T lymphocytes (CTL) present in peripheral blood of a patient with Th2-type SzS, focusing on the effect of IL-2, IFN-gamma and IL-12 on their cytotoxic activity, and the relationship between their lytic capacity and the patient's clinical course. At four different time points during a 2-month clinical period, CD4+CD7- Sézary cells and CD8+ cells were separated from the patient's circulating cells. CD8+ cells were cultured with chemically attenuated, purified Sézary cells in the presence of IL-2 to develop specific cytotoxicity. The CD8+ cells thus cultured exhibited lytic activity against autologous Sézary cells. Concomitant addition of IFN-gamma or IL-12 exerted a synergistic cytolytic effect with IL-2 on the tumour cells. Cytotoxicity inhibition studies using MoAbs revealed that the cytotoxicity operated in MHC class I-, CD8- and alphabeta T cell receptor-dependent manners. Furthermore, eight CD8+ T cell clones generated from cultured CD8+ cells exhibited a strong cytotoxicity against Sézary cells in an MHC class I-restricted fashion. During the clinical course, the activity of generated CTL and the number of CD8+ cells were inversely correlated with disease activity as assessed by the serum level of lactate dehydrogenase. These findings suggest that CTL down-regulate the growth of malignant T cells in this long-standing disease. Since Th2 cytokines such as IL-4 down-modulate CTL activity, CTL are assumed to be usually suppressed in SzS, whose malignant T cells are of Th2 type. It is likely that the administration of IFN-gamma normalizes this Th2-skewing state, activates CTL, and thus exerts the therapeutic effectiveness in the treatment of CTCL.

Spatially-regulated P-cadherin expression is crucial for maintaining the normal epidermal architecture. P-cadherin expression in cutaneous squamous-cell carcinomas (SCC) is altered, and may participate in tumor progression. We therefore investigated how P-cadherin expression was regulated in a cultured cutaneous SCC cell line (DJM-1). At low calcium concentration (0.05 mM), DJM-1 cells expressed P-cadherin weakly in the cytoplasm. At a higher calcium concentration, P-cadherin was promptly translocated to the cell surface within 30 min, gradually increased on the cell surface for up to 48 hr, and was continuously expressed for at least 7 days. During this time course, the total amount of P-cadherin protein had increased, whereas the steady-state mRNA levels for P-cadherin had not changed. The inhibition of protein synthesis by cycloheximide, but not the inhibition of gene transcription by actinomycin-D, completely suppressed the expression of P-cadherin. The effect of calcium was inhibited by tyrphostins but not by H-7, cholera toxin, or dibutylic cyclic AMP. Increments in the extracellular calcium concentration did not mobilize the intracellular calcium pool, and were accompanied by the tyrosine phosphorylation of a 62-kDa protein. In addition, DJM-1 cells expressed mRNA for a calcium-sensing receptor originally demonstrated in the parathyroid gland. The results suggest an unique mechanism for regulating P-cadherin gene expression in DJM-1 cells by extracellular calcium, which stimulates the de novo synthesis of P-cadherin at the translational level through protein tyrosine phosphorylation.

The expression pattern of epithelial (E)- and placental (P)-calcium-dependent cell-cell adhesion molecules was examined immunohistochemically in various skin tumors. E- and P-cadherin expression was preserved in nodular and superficial types of basal cell carcinoma (BCC). In well-differentiated squamous cell carcinoma (SCC), E-cadherin on the cell surface of the tumor was reduced but expression of P-cadherin was preserved more frequently at the peripheral sites of the tumor than in the central sites of the tumor. Paget's cells and melanoma cells did not express E- or P-cadherins in the nest of the epidermis. Immunoreactive E-cadherin levels in sera were significantly elevated in patients with invasive Paget's disease, metastatic malignant melanoma and severe types of psoriasis and atopic dermatitis when compared with those of normal controls. Reduced or loss of cadherin in localized tumor cells may be correlated with the proliferation, and the level of soluble E-cadherin in circulation may be a marker in the extent of damaged skin by tumor and/or inflammation.

Sézary syndrome is a leukemic variant of cutaneous T-cell lymphoma characterized by the appearance of numerous CD4+ cells with cerebriform nuclei in the peripheral blood. Recent observations have suggested that Sézary cells lack CD7 molecules on their surface and are analogous to murine Th2 cells. It remains unclear, however, whether these two properties are actually common features of Sézary cells. We describe a case of Sézary syndrome in which more than 98% of the peripheral blood mononuclear cells expressed CD7 as well as a homogeneous T-cell receptor V alpha 2V beta 17, indicative of the expression of CD7 in the Sézary cells. Although the circulating Sézary cells continuously bore CD7 molecule on their surface throughout the patient's clinical course, the intensity of CD7 expression was variable in skin-infiltrating and in vitro cultured cells. Peripheral blood mononuclear cells from the patient proliferated well to a V beta 17-relevant superantigen (staphylococcal enterotoxin B) but not to irrelevant superantigens; produced interleukin-2, interferon gamma, and tumor necrosis factor-alpha, but not interleukin-4; and transcribed messenger RNA for interleukin-2 and interferon gamma but not interleukin-4 or interleukin-10. This represents an unusual case of a CD7+ Sézary syndrome with a cytokine profile characteristic of Th1 cells.

Background: The administration of interleukin-2 (IL-2) has recently been reported to be favorable for treating malignant hemangioendothelioma (MHE)., Methods: Two patients with MHE responded well to intralesional injections of recombinant IL-2 (rIL-2) without major side effects. The purpose of this study was to characterize cells infiltrating the regressing tumor following rIL-2 treatment. Immunohistochemical studies were performed on biopsy specimens taken from rIL-2-injected lesional skin., Results: It was shown that CD8+ lymphocytes and CD56+ natural killer (NK) cells infiltrated at the rIL-2-injection sites, suggesting that these cells contributed to the tumor regression. In addition, MHE cells bore intercellular adhesion molecule-1 (ICAM-1) whose expression was augmented by rIL-2 injections., Conclusions: These findings suggested, that rIL-2 not only induces lymphokine-activated killer (LAK) cells and NK cells, but also facilitates these cytotoxic cells to adhere to MHE cells by enhancing ICAM-1 expression of tumor cells.

It has previously been shown that circulating Sézary cells respond in vitro to superantigenic staphylococcal exotoxins in a manner that is restricted by their V beta usage. This study was conducted to examine whether cutaneous colonization with Staphylococcus aureus influences the activity of the skin lesions of Sézary syndrome, and whether S. aureus isolated from patients with Sézary syndrome stimulates circulating Sézary cells in vitro. Two patients with Sézary syndrome, whose skin was colonized with S. aureus, were treated with antibacterial agents, and the relation between the severity of the skin disease and the degree of S. aureus colonization was assessed. In addition, the patients' peripheral blood mononuclear cells were cultured in the presence of mitomycin C-treated S. aureus or superantigenic staphylococcal toxins. The antibacterial treatment improved the skin disease, and eliminated S. aureus in both patients. In one patient, 98% of the peripheral blood mononuclear cells bore V alpha 2V beta 17 of the T-cell receptor, indicative of the presence of an extremely high percentage of circulating Sézary cells. The peripheral blood lymphocytes from this patient responded well in vitro to superantigenic staphylococcal enterotoxin (SE), but not to SEA or toxic shock syndrome toxin-1, or to mitomycin-treated S. aureus isolated from the same patient. Cutaneous colonization by S. aureus influences the disease activity of CTCL, possibly by activation of Sézary cells by bacterial superantigenic exoproteins.

Background: Halo congenital nevus is a condition in which halo formation is associated with congenital nevocellular nevi. Although several theories have been proposed, the immunologic mechanisms of halo formation and concomitant nevus regression still remain unclear. We presented immunologic findings in a case of halo congenital nevus with unique histologic location of inflammatory cells., Observations: Histologically, the present case of halo congenital nevus undergoing spontaneous regression showed a marked inflammatory infiltrate with remnants of original nevus cell nests. In the infiltrating T cells, CD8+ cells outnumbered CD4+ cells and the infiltrate of natural killer cells was not substantial. Direct and indirect immunofluorescence studies demonstrated the presence of IgM antibodies against nevus cells as well as melanoma cells and cultured melanocytes in the patient's serum., Conclusions: Our findings suggest that both T-cell-mediated immunity and IgM antibodies may be involved in the regression of halo congenital nevus. However, it is important to point out that our results may simply be epiphenomena and not directly responsible for the destruction of nevus cells.

A 76-year-old man presented with a 3-month history of a cutaneous nodule on the right thigh. The tumour was composed of CD3+, large atypical cells, and CD20+, small normal-appearing cells. Flow cytometry showed that CD20+ cells outnumbered CD3+ cells. By Southern blot hybridization analyses, the malignant cells were shown to be of T-cell origin, because of the presence of rearranged bands for the beta chain of the T-cell receptor, but not for the immunoglobulin heavy chain. This case represents a T-cell lymphoma intermingled with a large number of non-neoplastic B cells.

Background: Primary mucinous carcinoma is a rare primary adnexal neoplasm of the skin with a high recurrence rate., Objective: To improve the recognition of this clinical entity and aid in establishing the origin of this tumor., Methods: Two cases of this tumor were reported and investigated histopathologically and histochemically. Furthermore, some mucinous carcinomas arising from the breast or gastrointestinal tract were compared with this tumor., Results: Both cases showed no evidence of primary neoplasms as a source of metastasis and had characteristic findings of primary mucinous carcinoma of elongated cords and small lobules of epithelial cells floating in lakes of sialomucin. The origin of this tumor seemed to be an eccrine sweat gland., Conclusion: This tumor should be resected widely and, at least, the breasts and gastrointestinal tract should be investigated for primary lesions.

A case of systematized keratotic nevus which is a peculiar form of epidermal nevus is reported. The present case is rare because of the dysfunction of incomplete flexion of fingers by systematized keratotic nevus. Furthermore, it involved mixed clinical and histological changes of epidermal nevus from fingers to elbow. An operation with full-thickness skin graft was undertaken.

A 71-year-old man developed metastatic cutaneous nodules of colon carcinoma on the scalp and chest wall. Histopathological findings revealed aggressive invasion of the tumor cells into the overlying epidermis (epidermotropic carcinoma); they occasionally adhered to the epidermal cells. These morphological features have not been described in cutaneous metastases from internal carcinomas.

Four dermatofibromas (DF), 2 dermatofibrosarcomata protuberans (DFSP), 2 atypical fibroxanthmas of the skin (AFX), and one malignant fibrous histiocytoma (MFH) were studied by explant culture technique and scanning electron microscopy. Differences in the cellular atypism, phagocytic activity and motility were observed between histiocyte-like cells extending from a DF and DFSP group and an AFX and MFH group. Such cytological characteristics was maintained during in vitro transformation of the cells into fibroblastic cells. It was concluded that culture behaviors of the cells from each tumor group correlated well with in vivo growth and histologic features. We feel that examination of in vitro morphology of fibrous histiocytomas may prove useful in arriving at a correct diagnosis.

Application of the tumor-promoting agent 12-O-tetradecanoylphorbol-13-acetate (TPA) to mouse skin leads to a manifold induction of ornithine decarboxylase (ODC) activity within 5 hr and an increased accumulation of putrescine. The relevance of these TPA-induced changes to the mechanism of tumor promotion was investigated using alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of ODC. DFMO applied to mouse skin (0.3 mg in 0.2 ml of solvent) or administered in the drinking water (1%) in conjunction with skin tumor promotion by TPA inhibited the formation of mouse skin papillomas by 50 and 90%, respectively. TPA-induced ODC activity and the accumulation of putrescine were almost completely inhibited. DFMO given in the drinking water decreased spermidine levels, but DFMO treatment by any route did not alter the spermine levels of mouse epidermis. DFMO decreased TPA-induced hyperplasia by 25 to 40%, and the TPA-caused increases in DNA synthesis and mitotic index were inhibited by 60 and 50%, respectively. Therefore, in mouse epidermis, enhanced cell proliferation can be dissociated from ODC induction and the accumulation of putrescine. At the tested dose levels and routes of administration, DFMO did not inhibit the inflammatory response to TPA in several tissues. These results provide evidence for an essential role of ODC induction and the accumulation of putrescine in tumor promotion by TPA and add strength to the proposal that DFMO may be a promising drug for the prevention and treatment of cancer in human beings.

Data from three different sorts of experiments that were designed to provide additional information on the mechanism of tumor formation are presented. The aim of the first approach was to obtain further evidence for the possible relevance of the induction of ornithine decarboxylase (ODC) activity to tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA) in mouse skin. The irreversible inhibitor of ODC activity, alpha-difluoromethylornithine, not only prevented ODC activity in a dose-dependent manner following skin application, it also prevented skin tumor promotion by TPA. Because in tumor promotion experiments TPA must be applied repetitively in order to elicit tumors, the effect of various time intervals between two or more applications on ODC induction and polyamine levels was investigated. Double applications at intervals greater than 48 hr led to a larger induction of ODC than after a single application. In contrast, at intervals of 24 hr or less, the first application caused a refractory state; the second application did not induce ODC activity even at times after ODC activity had returned to the very low, control activity. The aim of the third approach was to more directly determine the function of TPA in the promotion process by identifying the receptor(s) for TPA and to ascertain the function of the receptor(s). A receptor was purified from the particulate protein fraction of mouse brain and it was found that divalent calcium and phosphatidylserine were essential for the maintenance of binding activity during purification. Furthermore the receptor copurified with protein kinase C; it may be that a TPA receptor is protein kinase C and that TPA activates phosphorylating activity.

Comparative studies were performed on clinical and laboratory features of four patients with different types of T-cell lymphoma of the skin; adult T-cell leukemia/lymphoma (ATLL), Sézary syndrome, mycosis fungoides, and Ki-1-positive lymphoma. All neoplastic cells studied showed a helper-inducer T-cell phenotype. A Ki-1-positive lymphoma is distinct from other types of cutaneous lymphomas because of unique morphologic and phenotypic features. Clonal proliferation of lymphocytes infected by human T-cell lymphotrophic virus (HTLV)-1 distinguishes ATLL from other T-cell lymphomas of the skin, especially in the endemic area of ATLL. From the pathogenic point of view, ATLL should not be included in a group with mycosis fungoides and Sézary syndrome.

Measurements of cell cycle kinetics using an immunoperoxidase method employing monoclonal anti-bromodeoxyuridine (BrdU) antibody were compared with an autoradiographic method using [3H]-thymidine. The methods were applied to epithelial cells grown from explants of normal skin and basal cell carcinoma (BCC), and to fibroblasts from normal skin, hypertrophic scar and keloid. In normal keratinocytes the number of peroxidase-positive cells was higher than the number incorporating [3H]-thymidine, because of the presence of labelled cells in the centre of the explants in the former. The epithelial cells from BCC gave a mean (+/- SD) of 4.9 +/- 1.2% peroxidase-positive cells, while no cells were labelled with [3H]-thymidine. In dermal fibroblasts from normal skin and hypertrophic scar the percentages of peroxidase-positive cells did not differ significantly from the [3H]-thymidine labelling indices. The immunological method has advantages over [3H]-thymidine autoradiography in that it avoids radioactive material and the proportion of cells labelled by the two methods is the same.

Cutaneous malignant lymphomas developed in an 80-year-old man without any evidence of leukemic disseminations of lymphoma cells. Immunohistologic staining showed the expression of Leu-3a, Leu-4, Ki-1, Tac, and HLA-DR antigens on tumor cells in tissue and large lymphoid cells in long-term, interleukin 2-containing culture of tumor explants. DNA samples extracted from the skin tumors and cultured lymphoid cells showed a clonal rearrangement of T-cell receptor (TCR) gene C beta 1 with the molecular size of 9 kilobases. These findings suggested the T-cell origin of Ki-1+ cutaneous lymphoma cells and the occurrence of a clonal proliferation of tumor cells in culture.