The anti-MAGE antibody B57 as a diagnostic marker in melanocytic lesions

Germ cell proteins in melanoma: prognosis, diagnosis, treatment, and theories on expression

Germ cell protein expression in melanoma has been shown to correlate with malignancy, severity of disease and to serve as an immunologic target for therapy. However, very little is known about the role that germ cell proteins play in cancer development. Unique germ cell pathways include those involved in immortalization, genetic evolution, and energy metabolism. There is an ever increasing recognition that within tumors there is a subpopulation of cells with stem-cell-like characteristics that play a role in driving tumorgenesis. Stem cell and germ cell biology is intertwined. Given the enormous potential and known expression of germ cell proteins in melanoma, it is possible that they represent a largely untapped resource that may play a fundamental role in tumor development and progression. The purpose of this paper is to provide an update on the current value of germ cell protein expression in melanoma diagnosis, prognosis, and therapy, as well as to review critical germ cell pathways and discuss the potential roles these pathways may play in malignant transformation.

Immune-related biomarkers for diagnosis/prognosis and therapy monitoring of cutaneous melanoma

Skin melanoma, a life-threatening disease, has a recently reported worldwide increase in incidence, despite primary prevention. Skin melanoma statistics emphasize the need for finding markers related to the immune response of the host. The mechanisms that are able to over-power the local immune surveillance comprise molecules that can be valuable markers for diagnosis and prognosis. This article summarizes the immune markers that can monitor the disease stage and evaluate the efficacy of therapeutic interventions. Recent data regarding immunotherapy are presented in the context of tumor escape from immune surveillance and the immune molecules that are both targets and a means of monitoring. Perspectives for developing immune interventions for skin melanoma management and the position of tissue or soluble immune markers as a diagnostic/prognostic panel are evaluated. State-of-the-art technology is emphasized for developing immune molecular signatures for a complex characterization of the patient's immunological status.

A mycoplasma peptide elicits heteroclitic CD4+ T cell responses against tumor antigen MAGE-A6

PURPOSE

Although T-helper (Th) epitopes have been previously reported for many tumor antigens, including MAGE-A6, the relevant HLA-DR alleles that present these peptides are expressed by only a minority of patients. The identification of tumor antigenic epitopes presented promiscuously by many HLA-DR alleles would extend the clinical utility of these peptides in vaccines and for the immunomonitoring of cancer patients.

EXPERIMENTAL DESIGN

A neural network algorithm and in vitro sensitization assays were employed to screen candidate peptides for their immunogenicity.

RESULTS

The MAGE-A6(140-170), MAGE-A6(172-187), and MAGE-A6(280-302) epitopes were recognized by CD4+ T cells isolated from the majority of normal donors and melanoma patients evaluated. Peptide-specific CD4+ T cells also recognized autologous antigen-presenting cell pulsed with recombinant MAGE-A6 (rMAGE) protein, supporting the natural processing and MHC presentation of these epitopes. Given the strong primary in vitro sensitization of normal donor CD4+ T cells by the MAGEA6(172-187) epitope, suggestive of potential cross-reactivity against an environmental stimulus, we identified a highly homologous peptide within the Mycoplasma penetrans HF-2 permease (MPHF2) protein. MPHF2 peptide-primed CD4+ T cells cross-reacted against autologous APC pulsed with the MAGE-A6(172-187) peptide or rMAGE protein and recognized HLA-matched MAGE-A6+ melanoma cell lines. These responses seemed heteroclitic in nature because the functional avidity of MPHF2 peptide-primed CD4+ T cells for the MAGE-A6(172-187) peptide was approximately 1,000 times greater than that of CD4+ T cells primed with the corresponding MAGE-A6 peptide.

CONCLUSIONS

We believe that these novel "promiscuous" MAGE-A6/MPHF2 Th epitopes may prove clinically useful in the treatment and/or monitoring of a high proportion of cancer patients.

Melanocytic “ball-in-mitts” and “microalveolar structures” and their role in the development of cellular blue nevi

To test the hypothesis of whether cellular blue nevi (CBN) may originate from "ordinary" compound and dermal nevi, a total of 275 melanocytic nevi including 59 CBN, 34 ordinary blue nevi, 87 combined nevi (including 43 so-called clonal nevi), 35 deep penetrating nevi, and 60 ordinary compound and dermal nevi (30 of each) were studied for the presence of so-called ball-in-mitts and microalveolar structures. A ball-in-mitts structure was defined as a single centrally placed melanocyte with a round to oval nucleus (the "ball" cell) and a clear, dusty, or pigmented cytoplasm encircled by a single dendritic cell (the "mitt" cell) with an oval to spindle-shaped nucleus and slender bipolar processes containing melanin and surrounding at least one fourth of the ball's diameter. A microalveolar structure was defined as a group of 2 to 10 centrally placed melanocytes with round to oval nuclei and clear, dusty, or pigmented cytoplasm (balls) surrounded by one or more cells (mitts) with spindle-shaped nuclei and slender bipolar processes containing melanin. Microscopically, ball-in-mitt and microalveolar structures were detected in all types of nevi studied, with the highest incidence in combined nevi (82%), CBN (76%), and ordinary "nonblue" nevi (73%). In CBN, ball-in-mitts and microalveolar structures tended to be located in the deeper portion of the lesions, whereas in ordinary nonblue nevi, they were most often found superficially, just below the epidermis; in clonal nevi, these structures were often confined to the "clonal" parts. Immunohistochemically, ball-in-mitts and microalveolar structures were positive for HMB45. Ultrastructurally, the balls tended to have round to oval nuclei, whereas the mitts possessed oval, elongated to spindled nuclei. Melanosomes were found in various stages in the cells of both structures. The cytoplasm of the mitts typically formed elongated polar processes, sometimes with club-like widenings at the ends, completely or partially encircling the balls. In the microalveolar structures, the adjacent cells forming the mitts surrounded the ball cells like a chain. Our study suggests that some or even most cases of CBN may evolve from ordinary nonblue nevi. This process may involve several steps and is probably reflected by the appearances of combined nevi, deep penetrating nevi, and CBN. These nevi often show a morphological overlap, and ball-in-mitts and microalveolar structures found in various stages of their development seem to greatly account for this overlap.

Cancer/testis antigen MAGE-A4 expression pattern differs in epithelial skin tumors of organ-transplant recipients and immunocompetent patients

BACKGROUND

Lifetime risk for squamous cell carcinoma (SCC) of the skin is 1:30. Risk in organ-transplant recipients (OTR) is increased over 60-fold through long-term drug-induced immunosuppression. MAGE family-derived peptides are cancer/testis antigens recognized by specific CD8(+) T cells and employed for immunotherapy. We were interested in the frequency and distribution of MAGE-A4 in epithelial skin tumors of OTR and immunocompetent patients.

METHODS

mAb 57B predominantly recognizing MAGE-A4 was used to stain 119 formalin-fixed, paraffin-embedded epithelial skin tumors (actinic keratosis, bowenoid actinic keratosis, Bowen's disease, and SCC; n = 17, 25, 61, 16, respectively) in immunocompetent patients (n = 84) and OTR (n = 35).

RESULTS

All four epithelial skin tumors showed comparable immunoreactivity ranging from (25-71%, p = 0.361). Scattered immunoexpression pattern was more frequent in OTR (p = 0.025). SCC showed polarized immunoreactivity basally (p = 0.002).

CONCLUSION

MAGE-A4 was expressed in a large part of epithelial skin tumors with predominantly scattered immunoexpression pattern in OTR. The difference in immunoexpression pattern for immune status was limited, suggesting important non-immunosuppressor-mediated mechanisms for increased skin carcinogenesis in OTR. mAb 57B may be a helpful tool for immunohistochemistry and micrographic surgery using formalin-fixed paraffin-embedded tissue.

Is melanocytic nevus with focal atypical epithelioid components (clonal nevus) a superficial variant of deep penetrating nevus?

BACKGROUND

We compare features of two similar nevi which may be confused with melanoma: deep penetrating nevus (DPN), and nevus with focal atypical epithelioid component (NFAEC).

METHODS

Clinical/demographic and histologic information regarding 146 DPN and 81 NFAEC were compared. Patient outcomes were ascertained via a questionnaire solicited to the referring physicians.

RESULTS

Clinical features were similar for each type of nevus. Histologically, all lesions demonstrated identical aggregates of epithelioid melanocytes. DPN more often extended into the deep dermis or subcutaneous tissue, while NFAEC was typically confined to the superficial dermis. NFAEC more often demonstrated a junctional component (P < .001) and coexistent common nevus with congenital features (P = .035). DPN more often demonstrated adnexal spread (P < .001). A subgroup with overlapping features was identified. With an average of 6.4 years follow-up, there were just two recurrences, and no metastases.

LIMITATIONS

This retrospective study utilized tissue specimens from a single reference laboratory; ergo, some inherent selection bias exists. Specimens were randomly selected for P53 immunostaining, leading also to potential sampling error.

CONCLUSIONS

DPN and NFAEC show considerable similarity, differing mainly in the depth of extent for the lesion. It is possible that NFAEC represents a more superficial variant of DPN. A subgroup with overlapping features, but intermediate depth, supports such a relationship.