Diagnostic relevance of chromosomal in-situ hybridization in Merkel cell carcinoma: Targeted interphase cytogenetic tumour analyses

B. K. Amo-Takyi, L. Tietze, K. Tory, P. Guerreiro, K. Günther, R. S. Bhardwaj, C. Mittermayer, S. Handt

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Aims: To resolve the conflicting diagnoses of five pathologists (which included well-differentiated neuroendocrine carcinoma, malignant carcinoid, undifferentiated small-cell carcinoma, primitive neuroectodermal tumour, metastases of small-cell lung carcinoma (SCLC) and Merkel cell carcinoma (MCC)), and tumour-free lungs after necropsy, we investigated an alarmingly metastasizing MCC in a 32-year-old Caucasian man using chromosomal in-situ hybridization (CISH). Differences in incidence and course in males and females also prompted targeted analyses for chromosomes X and Y. The lesion was also analysed for p53 gene mutations. Methods and results: Paraffin sections of the thorax, buccal lymph nodes and scalp tumours were stained with haematoxylin and eosin. Immunohistochemistry was performed with antibodies against pancytokeratin, keratin 20, neuron-specific enolase (NSE), chromogranin, neurofilaments and vimentin, among others. Sections (5-6 μm) of the tumours were analysed with α-satellite probes for chromosomes 1, 6, 7, 11, 12, 17, 18, X and Y using CISH; and exons 5-9 of the p53 gene were examined by polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP) methods. Although positive for pancytokeratin, keratin 20, chromogranin, NSE, synaptophysin and vimentin, the similarity in antigen profiles expressed by SCLC and MCC prevented a definitive tumour diagnosis. Chromosomal in-situ hybridization, however, revealed trisomies 1 and 11, two frequent aberrations in MCC, and trisomy 18. Moreover, 71% of the tumour cells had two to three copies of X, whereas 98% of the cell nuclei in the hair follicles and normal epidermis (purported Merkel cell origins) displayed one X chromosome. No mutations were detected in the five exons of the p53 gene examined. Conclusions: Had CISH been performed earlier, treatment may have been tailored specifically to suit MCC, since MCC and SCLC have different therapeutic strategies. Finally, chromosome X may be of prognostic relevance in MCC, which apparently predominates in females and yet shows poorer prognosis in males, and hence be worthy of further investigation.

Original languageEnglish
Pages (from-to)163-169
Number of pages7
JournalHistopathology
Volume34
Issue number2
DOIs
Publication statusPublished - Feb 23 1999

Keywords

  • Immunohistochemistry
  • Interphase cytogenetics
  • Merkel cell carcinoma
  • Mutation analysis
  • Small-cell lung carcinoma

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology

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