A study of MECT1-MAML2 in mucoepidermoid carcinoma and Warthin's tumor of salivary glands.
The t(11;19)(q21;p13) chromosomal translocation has been described in two distinct types of salivary gland neoplasms: mucoepidermoid carcinoma (MEC) and Warthin's tumor (WT). Since this translocation has been recently shown to generate a MECT1-MAML2 fusion gene, we evaluated 10 primary MEC and seven primary WT to further define the molecular association of these two entities using cytogenetic, as well as in situ hybridization (ISH) and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses directed against the fusion gene. A karyotype was established in all neoplasms except for two MEC cases. Of the eight karyotyped MECs, five showed the t(11;19)(q21;p13), two had a normal karyotype, and one case presented a -Y and +X. Three of the WT revealed a normal karyotype and four had several abnormalities which did not involve chromosomes 11 and 19. ISH analysis performed in cytogenetic suspension and/or in tumor paraffin sections demonstrated MAML2 rearrangement in 7 of 10 cases of MEC: all five cases with t(11;19), one case with normal karyotype, and one unkaryotyped case. RT-PCR analysis confirmed the expression of the MECT1-MAML2 gene in all MEC cases that were positive by ISH analysis. Neither the t(11;19) nor MECT1-MAML2 was detected in any case of WT, nor in control samples from polymorphous low-grade adenocarcinoma, acinic cell carcinoma, or normal parotid gland tissue. We have demonstrated that ISH and RT-PCR are sensitive methods for detecting MECT1-MAML2 in MEC. In contrast, we did not detect the t(11;19) nor MECT1-MAML2 expression in seven cases of WT.
Departamento de Patologia Morfológica, Instituto Português de Oncologia, Rua Prof. Lima Basto, 1099-023 Lisboa, Portugal.
Carmo
C
Martins
Branca
B
Cavaco
Giovanni
G
Tonon
Frederic J
FJ
Kaye
Jorge
J
Soares
Isabel
I
Fonseca
D000235:Adenolymphoma / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D018277:Carcinoma, Mucoepidermoid / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D015514:Oncogene Proteins, Fusion / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D012468:Salivary Gland Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology
C495418:MECT1-MAML2 fusion protein, human; D015514:Oncogene Proteins, Fusion; D012333:RNA, Messenger