Clinicopathologic characteristics of BRAF V600K mutant malignant melanoma

Bülbül G., Aysal Ağalar A., Yumuk E., Çağaptay S., Ellidokuz H., Lebe B.

34. Avrupa Patoloji Kongresi , Basel, Switzerland, 3 - 07 September 2022, vol.1, no.481

  • Publication Type: Conference Paper / Unpublished
  • Volume: 1
  • City: Basel
  • Country: Switzerland
  • Dokuz Eylül University Affiliated: Yes


Background & objectives: BRAF V600K mutation, the second most

common mutation in malignant melanoma with a rate of 10-30%, is

related to worse response to treatment and adverse prognosis. However,

data for comparing V600K/V600E groups for the histopathologic and

prognostic features are limited.

Methods: A total of 23 malignant melanoma cases with BRAF

V600E or BRAF V600K mutations detected by pyrosequencing

in our department were retrospectively analysed. The associations

between the type of BRAF mutations and histopathologic, clinical

and prognostic characteristics were statistically investigated.

Results: Of the 23 cases, 7 (30.4%) had V600K and 16 (69.6%)

had V600E mutation. Although there was no statistical significance

between two groups, most of the cases with V600K mutation were

male (85.7%). In BRAF V600K mutant cases, histologic type was

mostly superficial spreading melanoma (85.7%), tumour localization

was mostly head and neck (57.1%); ulceration and regression

were slightly higher. In BRAF V600E mutant group, the number

of mitosis (>10/HPF) was higher (81.3%). V600E mutant group

was generally more advanced (pT4) at the time of diagnosis (75%).

In survival analysis, the estimated survival time was shorter in

patients with V600K mutation than those with V600E mutation

(17.9 vs 33.2 months).

Conclusion: Although it’s a preliminary study and no statistical

significance was detected due to the low number of cases, our

results emphasize that overall survival time is almost half as

short in V600K mutant cases than those with V600E mutation.

Considering the prognostic differences, since the double nucleotide

change seen in the V600K mutation(GTG to AAG) includes the

single nucleotide change seen in the V600E mutation(GTG to

GAG), it’s important to be careful in the evaluation to distinguish

these two mutations.