Analysis of the association of BRAFV600E mutation and Ki-67 overexpression with clinical and pathological characteristics in papillary thyroid cancer

The Value of Ki-67 Labeling Index in Central Lymph Node Metastasis and Survival of Papillary Thyroid Carcinoma: Evidence From the Clinical and Molecular Analyses

BACKGROUND

Recent evidence suggests that the Ki-67 labeling index is associated with lymph node metastasis and the prognosis of papillary thyroid carcinoma (PTC).

METHODS

We retrospectively evaluated the clinicopathological features of consecutive PTC patients between Jan 2019 and Oct 2020 in our medical center. The molecular analysis was also conducted by using the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) program. The Chi-square test was performed for the comparison of variables between patients with central lymph node metastasis (CLNM) and not. Besides, univariate and stepwise multivariate logistic regression analyses were further used to determine the risk factors for CLNM in PTC.

RESULTS

Our results showed that male gender (odd ratio (OR) = 3.02; 95% CI: 1.81-5.04), tumor size >1 cm (OR = 2.81; 95% CI: 1.84-4.29), multifocality (OR = 2.08; 95% CI: 1.31-3.30, and Ki-67 labeling index (>3% and ≤5%: OR = 1.20; 95% CI: .73-1.97; >5%: OR = 3.85; 95% CI: 1.62-9.14) were independent risk factors for CLNM. After excluding the patients with harvested central lymph nodes <3, increased Ki-67 labeling index was still associated with the number of CLNM and the lymph node ratio. Additionally, the expression level of Ki-67 was significantly correlated with a higher N stage and worse disease-free survival in TCGA and validated GSE60542 datasets.

CONCLUSIONS

Higher Ki-67 labeling index (>5%) is significantly associated with the CLNM in PTC patients, like other indicators of the male gender, larger tumor size, and multifocality. Besides, the Ki-67 was also determined to be associated with CLNM and DFS in PTC patients, which may act as an important molecular marker in PTC.

Correlation of the Expression of BRAF V600E Mutation With Various Phenotypic Expressions of Thyroid Neoplasms

Aims We aimed to assess the incidence of the BRAF V600E mutation in thyroid neoplasms at a tertiary care center and its association with various phenotypic features. Methods and material We included all cases diagnosed as thyroid neoplasm in the past decade at the Department of Pathology of our institute and obtained their clinical details from the medical records department of the institute after obtaining permission from the authorities and due International Human Epigenome Consortium clearance. We included data on age, sex, clinical presentation, hormone status, and T and N status of the malignant neoplasms. Hematoxylin and eosin (H&E) slides of all cases were evaluated for the type of neoplasm, nuclear features, invasion into the capsule and vascular spaces, extrathyroidal extension, lymph node metastases, mitoses, necrosis, and presence/absence of amyloid. Paraffin blocks of sections with high tumor density and less normal tissue were chosen for evaluation after H&E staining. The slides showing tumors with large areas of hemorrhage, cystic change, or necrosis were excluded. Two primers were used to amplify a 339-bp fragment containing the V600E mutation in exon 15 of BRAF. Tissues were prepared from formalin-fixed paraffin-embedded (FFPE) blocks, and DNA was isolated using a standard protocol BRAF NF and BRAF NR Primer Standardized Protocol For FFPE Tissue DNA. Percentages and tables have been used for data presentation. Results Among 47 identified cases, 14 were positive for the BRAF V600E mutation and had papillary carcinoma (n = 9) or follicular neoplasms (n = 5; follicular adenoma, n = 3; follicular carcinoma, n = 2). In the BRAF-positive papillary carcinomas, five cases were aged 20-30 years, eight were female, eight (88.88%) were euthyroid, and one was hypothyroid. Furthermore, 55.55% (5/9 cases) of BRAF-positive cases were stage I, 33.3% (3/9 cases) were stage II, and 0.02% (1/9 cases) were stage III. Conclusions In our cohort, 31% of cases of papillary thyroid carcinoma (PTC) and 18.72% of follicular neoplasms expressed the BRAF V600E mutation. BRAF V600E mutation-positive papillary thyroid carcinomas consistently showed all characteristic nuclear features, such as nuclear crowding, overlapping, and grooves. Considering the greater prevalence in the younger age group, the importance of mutation surveillance in PTCs for a total thyroidectomy may be warranted in mutation-positive patients.