Case 64

A 73-year-old female presented with a submandibular mass.

1. Which translocation is most commonly found in MECs, leading to the expression of the CRTC1::MAML2 fusion gene?

   A. t(11;19)(q21;p13)

   B. t(11;15)(q21;q26)

   C. t(6;22)(p21;q12)

   D. t(19;11)(p13;q21)

   
   

Answer

A. t(11;19)(q21;p13)

2. Which tumor grade in MECs typically exhibits negligible copy-number variation and few somatic mutations, such as TP53 and POU6F2?

A. High-grade MECs

B. Intermediate-grade MECs

C. Low-grade MECs

D. All tumor grades equally

Answer

 C. Low-grade MECs.

Translocation	Fusion Gene	Frequency/Occurrence	Tumor Grade Association
t(11;19)(q21;p13)	CRTC1::MAML2	Most MECs (common)	Predominantly in low- and intermediate-grade tumors; also in some high-grade tumors
t(11;15)(q21;q26)	CRTC3::MAML2	Rare cases	Not specifically defined
t(6;22)(p21;q12)	EWSR1::POU5F1	Highly unusual	Not specifically defined

Additional Note: Low-grade MECs show negligible copy-number variation and few somatic mutations (e.g., TP53 and POU6F2).