Several genes implicated in the development of various malignancies appear to be of minor relevance in melanoma. We therefore aimed to find a tumour suppressor candidate involved in this malignancy by comparing gene expression in uncultured primary melanoma specimens with those in acquired melanocytic naevi, from which quite often melanomas are known to arise. Applying the subtractive suppression hybridization technique, we generated a subtracted library of candidate genes downregulated in melanoma. Among the cDNA fragments identical to known genes, this library included a cDNA fragment 630 bp in length that is identical to the gene for the human protein phosphatase 2A (PP2A) regulatory subunit B (B56) gamma isoform (PP2A-Bgamma, PPP2R5C). On further evaluation of 15 primary melanoma and 16 acquired melanocytic naevus tissue specimens from independent patients using semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis, expression of this gene was found to be suppressed in melanomas compared with naevi; the difference was statistically significant. As PP2A is known to be a major cellular serine-threonine phosphatase, and has been implicated not only in the regulation of cell growth and division but also in the control of gene transcription and growth factor signal transduction, alterations in the pattern of the regulatory subunits may affect substrate specificity and subcellular localization of the PP2A holoenzyme in melanoma cells.

During recent years it has become evident that protein kinase B (PKB)/Akt plays an important role in oncogenic transformation. The gene for PKB/Akt has been found to be overexpressed in certain human tumours and a viral fusion protein gains transforming capacity. Recruitment to the plasma membrane is mandatory for the physiological activation of PKB/Akt; this shift from cytoplasm to the membrane is achieved by the N-terminal pleckstrin homology (PH) domain. We attempted to find out whether mutations of this domain were present in human malignant melanoma. RNA from 18 primary melanoma lesions of different sizes and histological subtypes and two melanoma metastases from 20 Caucasian patients were used for reverse transcription and subsequent polymerase chain reaction (PCR) amplification of the PH domain of PKB/Akt alpha. Cycle sequencing of the purified PCR products showed that mutations of the PH domain of PKB/Akt were absent in all 20 melanoma specimens. In virtual Northern hybridizations PKB/Akt showed a low expression in both melanomas and acquired melanocytic naevi; however, no overexpression of PKB/Akt was detected. Thus in human melanoma PH domain mutations of PKB/Akt do not play a major role in melanoma carcinogenesis.

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Erythema elevatum diutinum is a rare chronic inflammatory skin disease of unknown etiology with a histopathology of a leukocytoclastic vasculitis. Clinical findings involve symmetrical livid-erythematous to red-brown papules and plaques or nodules which are initially soft but become firmer. The skin lesions are located over extensor surfaces and often over joints. Early treatment with dapsone, corticosteroids and antibiotics is sometimes effective. A patient with multiple myeloma displayed unusual lesions of erythema elevatum diutinum.

BACKGROUND Dissection of the “sentinel lymph node” (SLN) as identified by lymphoscintigraphy is becoming increasingly important in the treatment of patients with malignant melanoma. The purpose of the current study was to determine whether the SLN also could be identified by ultrasound. METHODS Sixty‐seven patients with malignant melanoma (40 females and 27 males, with an average age of 48.8 years) in whom extirpation of the SLN was indicated underwent ultrasonography of the regional lymph nodes prior to preoperative lymphoscintigraphy. The location of the melanoma was the legs in 30 patients, the arms in 14 patients, and the trunk in 23 patients. During regional ultrasonography, the location of the lymph nodes that differed in the cortex/medulla ratio from the surrounding lymph nodes was marked on the skin corresponding to the planes of insonation (M1) when the probe was held vertically to the skin surface. After lymphoscintigraphy using technetium‐99m, the position of a gamma probe at which the highest count rate vertical to the skin surface was recorded also was marked (M2). RESULTS In the inguinal region, the agreement between M1 and M2 was found to be 100% (40 of 40 SLNs) and was 72.5% in the axilla (29 of 40 SLNs). In patients with melanomas located on the leg, the location of M1 and M2 agreed in 97% of cases (36 of 37 lymph nodes in 30 patients); in patients with melanomas located on the arms, the agreement was 76% (13 of 17 lymph nodes in 14 patients) and in patients with melanomas located on the trunk, the agreement was 75% (21 of 28 lymph nodes in 23 patients). The position documented by ultrasound relative to the neighboring structures of the SLN was confirmed intraoperatively in all cases. CONCLUSIONS The results of the current study indicate that the SLN in patients with melanoma located on the limbs, especially the legs, are characterized by a specific sonomorphologic pattern. Preoperative sonography might constitute an important addition to lymphoscintigraphy in the planning of SLN biopsy. Cancer 2003;97:1947–54. © 2003 American Cancer Society. DOI 10.1002/cncr.11261