Expression of β-catenin and cyclin D1 in Merkel cell carcinomas of the head and neck

BACKGROUND

Merkel cell carcinomas (MCC) are very aggressive tumors of the sun-exposed skin with a high potential to metastasize. Little is known about the genesis of MCC and very few prognostic markers have been detected so far. The Wnt pathway protein β-catenin and the cell cycle protein cyclin D1 are two promotors of tumor growth and are expressed in a variety of malignant neoplasms such as lymphomas, thyroid, breast cancer, and many others.

PATIENTS AND METHODS

Tissue samples of 27 patients with MCC were immunohistochemically stained for β-catenin and cyclin D1 and correlated with overall survival of patients. In addition, western blot analysis was carried out in the two MCC cell lines MCC-13 and MCC-26.

RESULTS

β-catenin showed a cytoplasmatic expression of 10-30 % in 11 samples and an expression lower than 10 % in eight samples. Nuclear staining was visible in two samples. None of the 27 samples expressed cyclin D1.

CONCLUSION

Neither cyclin D1 nor β-catenin was expressed in a statistically significant manner, concluding that the development of MCCs is independent of β-catenin and cyclin D1 expression and these proteins are not suitable as prognostic markers. We could describe the expression pattern of cyclin D1 for the first time.

Merkel cell carcinoma - description of five cases

Merkel cell carcinoma (MCC) is a rare but very aggressive skin cancer that derives from neuroendocrine cells of the skin. Merkel cell carcinoma morbidity has been continuously increasing for the last few years. Increasing reported incidence of MCC is probably connected with increasing occurrence of this kind of malignancy or with development of histological and immunohistochemical methods of sample examinations which have allowed for more precise diagnosis of skin tumor that might have previously not been accurately recognized. Merkel cell carcinoma develops as nodules early recognized as basocellular carcinoma, squamous cell carcinoma, amelanotic melanoma or skin lymphoma. Merkel cell carcinoma can be morphologically similar to skin metastasis as well as mild changes such as lipoma, cysts, fibroma or vessel changes. Accurate diagnosis is very important because it determines successful management and risk of progression of disease. We describe 5 patients with MCC who underwent surgical excision and then, after estimation of stage of disease, complementary treatment. Our observations prove that every tumor with MCC should be cut out with wide margins and regional lymphadenectomy or sentinel node biopsy is compulsory. After cutting out MCC involved-field radiotherapy is necessary and improves prognosis. Presence of metastases in lymphatic nodes is an indication for complementary chemotherapy.

Intracranial spread of Merkel cell carcinoma to the cerebellopontine angle

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, highly malignant, and aggressive dermal neuroendocrine neoplasm that rarely metastasizes to the central nervous system.

OBJECTIVE

To review the current literature regarding treatment of neurometastatic MCC.

METHODS

A case of a 78-year-old male with intracranial extra-axial metastatic MCC involving the left cerebellopontine angle is presented.

RESULTS

A retrosigmoid craniectomy was performed with complete resection of the metastatic focus. Adjuvant treatment included whole-brain radiation therapy followed by etoposide and carboplatin chemotherapy. Seven months postoperatively, the patient was free of metastatic disease.

CONCLUSION

Surgical resection should be performed when feasible to prevent local recurrence. This may be followed by early adjuvant fractionated whole-brain radiotherapy and systemic chemotherapy; however, no clinical trials have been performed to demonstrate a survival benefit.

Five hundred patients with Merkel cell carcinoma evaluated at a single institution

OBJECTIVE

To identify factors associated with survival in Merkel cell carcinoma (MCC).

BACKGROUND

Merkel cell carcinoma is a rare cutaneous neoplasm. Staging and treatment are based on studies, which incompletely characterize the disease.

METHODS

Review of a prospective database was performed. Overall survival (OS) was estimated by the Kaplan-Meier method. Disease-specific death (DSD) was analyzed by the competing risks method. Factors associated with OS and DSD were determined by the log-rank test and Gray's test, respectively.

RESULTS

A total of 500 patients with MCC treated at our institution from 1969 to 2010 were identified. Eighty-eight patients presented older than 6 months after diagnosis and were excluded from further analysis. Of the remaining 412 patients, the median age at diagnosis was 71 years. Median follow-up was 3 years. Fifty percent of patients died during follow-up: 25% died of disease, 24% died of other causes. Five-year OS and DSD were 56% and 30%, respectively. Pathologic stage and lymphovascular invasion were independent predictors of DSD. Patients with metastatic disease (stage 4) or clinically positive lymph nodes (stage 3b) had increased DSD compared with patients with microscopically positive (stage 3a) or negative lymph nodes (stage 1 and 2). There was no difference in DSD between stage 3a or 2 compared with stage 1. Importantly, only 1 of 132 patients without lymphovascular invasion died of MCC.

CONCLUSIONS

OS is a poor measure of the influence of MCC on life expectancy. The presence of lymphovascular invasion and clinically, but not microscopically, positive lymph nodes were associated with increased DSD. These factors should be incorporated into MCC staging and treatment recommendations.

P53 mutation is a rare event in Merkel cell carcinoma of the head and neck

The aim of this retrospective analysis was to evaluate the status of p53 and possible mutations in Merkel cell carcinoma (MCC) cell lines and MCC tissue samples. The p53 mutations are common in different cancer origins but rare in MCCs detected so far. MCCs are highly aggressive neuroendocrine tumors with an enhanced potential to metastasize. Until now, less is known about MCC and new approaches to understand this disease are necessary. RNA and DNA were extracted from two MCC cell lines and 27 archival paraffin-embedded patient samples. After reverse transcription, a real-time PCR and a high-resolution melt analysis were carried out. In both MCC cell lines, we could detect a p53 missense mutation at codon 193 (exon 6) with a change in amino acids (His → Leu). This mutation was equal in both cell lines and was investigated in 27 tissue samples in succession to detect possible accounts for the aggressive behavior of MCCs. Unfortunately, no corresponding p53 mutation could be observed in the investigated tissue samples. A new p53 mutation was detected in MCC cell lines. This mutation could not be determined in patients' samples. Therefore, the aggressiveness of MCC seems to be independent of p53 mutations and other mutations might be responsible for developing MCC.