ALK-associated papillary thyroid carcinoma

Pathogenic ALK translocations have been reported in papillary thyroid carcinoma (PTC). 2.2% of PTCs are ALK-translocated and can be identified by screening IHC followed by FISH. (25501013)

In a study (25501013), all 14 patients with ALK translocations were female (P=0.0425), and translocations occurred at a younger age (mean 38 vs. 48 y, P=0.0289 in unselected patients).

ALK translocation is an early clonal event present in all neoplastic cells and mutually exclusive with BRAF mutation.

ALK translocation is not associated with aggressive clinicopathologic features (size, stage, metastasis, vascular invasion, extrathyroidal extension, multifocality, risk for recurrence, radioiodine resistance). No ALK translocations were identified in 36 PTCs with distant metastases, 28 poorly differentiated (insular) carcinomas, and 20 anaplastic carcinomas. (25501013)

ALK translocations may be more common in young females and diffuse sclerosing variant PTC but do not connote more aggressive disease. (25501013)

Open References

 A Detailed Clinicopathologic Study of ALK-translocated Papillary Thyroid Carcinoma. Chou A, Fraser S, Toon CW, Clarkson A, Sioson L, Farzin M, Cussigh C, Aniss A, O’Neill C, Watson N, Clifton-Bligh RJ, Learoyd DL, Robinson BG, Selinger CI, Delbridge LW, Sidhu SB, O’Toole SA, Sywak M, Gill AJ. Am J Surg Pathol. 2014 Dec 11. PMID: 25501013