Primary Malignant Melanoma Lesions Research Articles

Dimerization Co-Factor of Hepatocyte Nuclear Factor 1/Pterin-4α-Carbinolamine Dehydratase Is Necessary for Pigmentation in Xenopus and Overexpressed in Primary Human Melanoma Lesions

Dimerization co-factor of hepatocyte nuclear factor 1 (HNF1)/pterin-4alpha-carbinolamine dehydratase (DCoH/PCD) is both a positive co-factor of the HNF1 homeobox transcription factors and thus involved in gene regulation as well as an enzyme catalyzing the regeneration of tetrahydrobiopterin. Dysfunction of DCoH/PCD is associated with the human disorders hyperphenylalaninemia and vitiligo. In Xenopus, overexpression of the protein during development induces ectopic pigmentation. In this study loss of function experiments using DCoH/PCD-specific antibodies demonstrated that the protein is also absolutely necessary for pigment cell formation in Xenopus. In normal human skin DCoH/PCD protein is weakly expressed in the basal layer of the epidermis that consists of keratinocytes and melanocytes. Whereas only 4 of 25 benign nevi reacted with DCoH/PCD-specific antibodies, high protein levels were detectable in melanoma cell lines and 13 of 15 primary malignant melanoma lesions. The comparison with the commonly used melanoma markers S100 and HMB45 demonstrated that DCoH/PCD has an overlapping but distinct expression pattern in melanoma lesions. In addition to human colon cancer, this is the second report about the overexpression of DCoH/PCD in human tumor cells indicating that the protein might be involved in cancerogenesis.

Cathepsin A activity in primary and metastatic human melanocytic tumors.

Several lysosomal proteases including cathepsins B, D, H and L have been found to play a role in the metastasis of tumor cells. However, up to now no information on the role of cathepsin A, a lysosomal multifunctional peptidase, in the proliferative, invasive, and metastatic potential of malignant tumors has been available. In the present study we compared the activity of cathepsin A in lysates of 34 human melanocytic tumors: primary (n = 12) and metastatic (n = 5) malignant melanoma, dysplastic pigmented nevi (n = 6) and pigmented nevi without evidence of dysplastic melanocytes (n = 11). The carboxypeptidase activity of cathepsin A was assayed at pH 5.0 with its specific substrate Cbz-Phe-Ala. The amount of released C-terminal alanine was measured by the ninhydrin method. We found that lysates of primary malignant melanoma lesions exhibited significantly higher cathepsin A activity than lysates of dysplastic and normal pigmented nevi. The cathepsin A activity in lysates of metastatic lesions of malignant melanoma was significantly higher than in primary focus lysates. It seems that cathepsin A may play a role in malignant transformation and metastatic dissemination of malignant melanoma.

顎下リンパ節に発症した原発巣不明の悪性黒色腫の１例

We report a case of malignant melanoma of unknown primary origin that was found in the submandibular lymph nodes. A 63-year-old man presented on April 19, 1996 because of a swelling in the right submandibular region. The lesion measured 48 × 38mm and had no spontaneous pain. We planned to perform an excisional biopsy for histological diagnosis, but the patient refused the operation because the lesion had shrunk to about one half of its maximal size. The patient was therefore followed up.By June 1997, the lesion had grown rapidly, measuring 60 × 50mm. We suspected a malignant lesion, probably malignant lymphoma, from the results of a computed tomographic scan and 67Ga scintigraphy. On July 3, 1997, we performed surgical excision and made a histopathological diagnosis of malignant melanoma with lymph node metastasis. However, there was no evidence of a primary lesion of malignant melanoma in the skin, mucosa, eyes, or digestive system.

Strong expression of the lymphoattractant C-X-C chemokine Mig is associated with heavy infiltration of T cells in human malignant melanoma.

Human malignant melanoma (MM) is a highly aggressive tumour which is particularly prone to specific local immune responses. To determine the microanatomical location and the species of chemokines possibly involved in the intricate control of cell migration and positioning of immune effector cells in primary and metastatic MM lesions, the expression of those chemokines with lymphocyte and/or macrophage chemoattractant properties was analysed by in situ hybridization. GROalpha (growth-related oncogene) and IL-8 (interleukin 8) were expressed at low levels by single melanoma cells, adjacent keratinocytes, and infiltrating leukocytes. In contrast, the lymphocyte-specific chemokine Mig (monokine induced by interferon-gamma) was strongly expressed by mononuclear cells (mainly macrophages) infiltrating the tumour margin in primary MM lesions, whereas expression was less intense in MM metastasis. IP-10 (interferon-gamma inducible protein 10) was expressed in the same loci at lower intensity. Marked infiltration of T cells was exclusively detected in those areas which exhibited strong Mig expression, whereas areas in the vicinity of tumour cells devoid of Mig expression were not infiltrated. In contrast to Mig, expression of MCP-1 (macrophage chemotactic protein-1) was weaker and mainly detected in lesional basal keratinocytes, occasionally at sites of macrophage infiltration, as well as in single melanoma cells. MIP-1alpha (macrophage inflammatory protein 1alpha) showed similar, albeit weaker expression compared with MCP-1. Other chemokines relevant for the recruitment of monocytes and lymphocytes, such as RANTES (regulated on activation, normal T cells expressed and secreted) and MIP-1beta, were barely detectable. In summary, the chemokine expression profiles support the notion that particularly in heavily infiltrated primary MM lesions, Mig and to a lesser extent IP-10 are important mediators of an IFN-gamma-dependent pathway. Due to their lymphoattractant properties and the known inhibitory effects on the tumour vasculature, both chemokines may be critical for the control of local melanoma tumour growth.

Angiogenesis and vascular growth factor receptor expression in malignant melanoma.

The growth and metastases of many solid tumors are dependent on the recruitment of new blood vessels. Tumor angiogenesis is most likely initiated by paracrine release of growth factors that bind to their corresponding endothelial cell surface receptors. To determine whether angiogenesis and growth factor receptor expression are consistent findings in malignant melanoma, primary human melanomas were examined for mRNA expression of receptors for fibroblast growth factors (FGFR-1, FGFR-2), vascular endothelial growth factor (VEGFR-1, VEGFR-2), and the receptors Tiel and Tie2. Charts were reviewed and archival formalin-fixed, paraffin-embedded primary tumors were obtained from patients with thin (<1 mm; n = 10), intermediate (1 to 4 mm; n = 10), or thick malignant melanoma (>4 mm; n = 8). Also examined was whether melanoma cell lines could induce endothelial growth factor receptor synthesis by metabolic labeling. It was found that tumor vascularity did not correlate with clinical stage, melanoma thickness, or clinical outcome. It was also found that melanoma cell lines were not capable of directly regulating endothelial cell synthesis of growth factor receptors. However, expression of Tiel and VEGFR-2 mRNA by the tumor vasculature in select stage IA-IIB patients, and FGFR-1 mRNA expression by the tumor cells in the same clinical stages was found. The expression of these growth factor receptors did not correlate with clinical outcome. These data suggest that angiogenesis is not a prominent characteristic of primary malignant melanoma lesions and that the endothelial cell expression of Tiel and VEGFR-2 in vivo is probably not directly induced by the tumor.

Development and characterization of rabbit antisera to human MHC-linked transporters associated with antigen processing.

The limited availability of sera to human MHC-linked transporters associated with antigen processing (TAP) has hampered the analysis of the role of these molecules in the reduced HLA Class I antigen expression by normal and transformed cells. To overcome these limitations, anti-human TAP1 and anti-human TAP2 xenoantisera have been generated and characterized. To this end rabbits have been immunized with TAP1-specific or TAP2-specific peptides which correspond to nonhomologous, hydrophilic regions of each transporter subunit. The immunized rabbits developed high titer IgG antibodies which displayed specific reactivity with the immunizing peptides in ELISA. Both anti-TAP1 and anti-TAP2 antisera immunoprecipitated the 70-76 kDa TAP complex from TAP(+)-TAP2+ cell lines WALK and Colo 38, but precipitated no component from TAP(-)-TAP2- cell lines T2 and SK-MEL-19. Furthermore, in immunodepletion experiments anti-TAP1 and anti-TAP2 antisera removed the molecules recognized by each of them in a lymphoid cell extract. Lastly, in Western blotting assays anti-TAP1 and anti-TAP2 antisera reacted specifically with isolated TAP1 and TAP2, respectively. The latter results in conjunction with those of the immunodepletion experiments indicate that TAP1 and TAP2 are not detectable as isolated subunits in a cell extract and that TAP heterocomplex is the major, if not the only detectable molecular species in cells. Anti-TAP1 and anti-TAP2 antisera were evaluated in immunohistochemical staining of both frozen and formalin fixed sections of skin and primary malignant melanoma lesions. Both antisera stained the cytoplasm of keratinocytes in normal skin and of melanoma cells in malignant lesions. The antisera we have elicited with TAP1- and TAP2-specific peptides appear to be useful reagents to characterize the role of TAP in abnormalities of HLA Class I antigen expression.

5-S-cysteinyldopa in urine and tumors.

1) The urinary 5-S-CD contents in malignant melanoma subjects (n = 135) and non-melanoma subjects (n = 204) were measured by HPLC. These results suggest that, as a biochemical marker, periodic measurement of urinary 5-S-CD is quite useful for evaluating the determinations of stage classification (UICC, 1987), and the detection of metastases, the therapeutic efficacy of operation or immunochemotherapy against malignant melanoma. 2) Quantitative analyses of 5-S-CD values in tissues from primary malignant melanoma lesions (n = 24) and pigmentary tumors other than melanomas (n = 136) showed 80.6-821.4 ng/mg and N.D.-55.0 ng/mg respectively. In view of the above findings, it was suggested that the pigmentary tumors can be diagnosed as malignant melanoma if the 5-S-CD value in the tissues is higher than 100 ng/mg.

Prognostic significance of proliferation and motility in primary malignant melanoma of the skin.

The metastatic cascade depends on the presence of tumor cells which are capable of proliferation as well as of invasion with active motility. In the present study, it was examined whether the demonstration of both features in the primary lesion of malignant melanoma of the skin carries prognostic significance. Proliferation was assessed by mitotic counts and Ki 67 staining, and motility was estimated by image analysis and comparison of the image analysis results with computer simulations; 27 cases of primary malignant melanoma with a maximum vertical tumor thickness exceeding 1 mm were prospectively sampled. Mitotic counts were carried out on H & E stained sections, image analysis of the tumor pattern on S-100 immunostained paraffin slides, and Ki 67 labeling of actively cycling cells was evaluated on frozen sections. Neither proliferation nor pattern analysis alone provided a significant prognostic result with respect to overall survival and to metastasis free survival. The estimates of motility, derived from a combination of pattern analysis and proliferation values, however, proved to be significant predictors of overall survival and metastasis-free survival (log rank test: p less than or equal to 0.05). The motility features were superior to Clark level and Breslow index in this set of cases. The results demonstrate that the assessment of tumor cell proliferation and motility in histological sections may reflect the metastatic potential of primary malignant melanomas of the skin.

悪性黒色腫に対する陽子線療法の試みについて

In 7 patients the primary lesion of malignant melanoma was treated with proton beams in Proton Medical Research Center, University of Tsukuba. Four cases were male and the other 3 were female. Five cases were acral lentiginous melanomas and the other 2 were superficial spreading melanomas. Two cases received 3 to 8Gy fractions administrated 15 or 16 times in 24 or 44 days to a total dose of 90 or 91Gy. The other patients received even higher single doses than them, i.e. large fraction radiotherapy. They received 10 to 13Gy fractions administrated 7 to 11 times in 9 to 18 days to a total dose of 91 to 110Gy. Clinically the tumor reacted to the irradiation and in 6 cases showed partial regression of the size with erosive reaction, and in one case showed complete regression with complete healing of moist desquamation. Histological examinations were performed in 4 cases and they showed many melanoma cells degenerated. Electromicroscopic examination revealed that the organelle and the nucleus highly degenerated. Results indicated good local effects were obtained by proton beams, although additional modalities were requested to manage the remaining tumors.Malignant melanoma is considered unresponsive to conventional radiation therapy in part due to a large shoulder on the radiation survival curve and higher dose fractions might be beneficial. The superior dose distribution of proton beams allows high-dose exposure to the target area with lesser dose to the surrounding normal tissues. And it enables one to treat malignant melanomas with as high single doses as 10 Gy like in the 5 cases, expecting that repair process of melanoma cells would be overcome. It is postulated that proton therapy should allow malignant melanoma to be treated with even higher doses resulting in improved local control rates.

Spontaneous Partial Regression of Primary Melanoma With Death due to Metastases

A 42-year-old man had a metastatic melanoma in the brain, but no obvious primary melanoma could be detected. A halo nevus-like depigmented lesion was found on the left side of the patient's back. The histopathologic features of the depigmented lesion were compatible with those of a spontaneously regressed primary lesion of malignant melanoma. Enhanced immune responses to autologous and homologous melanoma cells were not detected when investigated in the late disease stage. Subsequently, the patient died of disseminated melanoma.

Characteristics of the primary lesion of malignant melanoma as a guide to prognosis and therapy

Characteristics of the primary lesion of malignant melanoma as a guide to prognosis and therapy

Characteristics of the Primary Lesion of Malignant Melanoma as a Guide to Prognosis and Therapy

The histologic materal from the original lesion of 113 patients suffering from Clinical Stage I and Clinical Stage II malignant melanomas were reviewed in an attempt to correlate depth of invasion with prognosis and to test whether or not current methods of microstaging were a valid guide to therapy. Both the microstaging methods of Clark and Breslow were eminently successful in indicating the prognosis of the patient, but were of no greater utility than other histologic parameters such as mitotic activity, perineural, vascular, or lymphatic invasion, or the presence of superficial ulceration. The value of elective node dissection for the treatment of primary malignant melanoma is uncertain. Deterents against empiric dissection are its low yield of occult metastases, its inability to prevent recurrence in a substantial portion of patients independent of the status of the nodes, and the difficulty in demonstrating an improved survival rate when this method of therapy is employed. Neither Clark's nor Breslow's methods or microstaging appeared to yield adequate criteria by which to choose node dissection. A simplified method of microstaging is proposed utilizing well defined anatomic levels, and yields statistically valid criteria for the performance of elective node dissection. Using this method, elective node dissection is advocated solely for those tumors that clearly invade the reticular dermis. Patients with tumors restricted to the papillary dermis do not appear to be benefited by empiric node dissection.

SPONTANEOUS REGRESSION OF THE PRIMARY LESION OF A METASTATIC MALIGNANT MELANOMA

An atypical elderly patient with spontaneous regression of a primary lesion of malignant melanoma is presented. The 12 previously reported cases are also reviewed. The histological diagnosis of spontaneous regression of a melanoma can still be made after the regression appears to be grossly complete. All localized areas of depigmentation, or of scarring, should be biopsied when searching for an "occult" primary.