Genetic expressions alteration affect on lateral neck node metastasis of thyroid papillary microcarcinoma

We performed oligonucleotide microarray analysis to assess the genetic expression alteration wich affected on lateral neck node metastasis of thyroid papillary microcarcinoma(PTMC). We performed microarray analysis in three PTMCs without cervical lymph-node metastases (N0), and five PTMCs with lateral neck-node metastasis (N1b) at initial diagnosis, using an Illumina HumanHT-12 v4.0 Expression BeadChip. Total 16 samples (3 T1aN0 PTMC and 5 T1aN1b or T3N1b PTMC(papillary thyroid microcarcinoma) and its paired normal thyroid tissue) were used. We obtained thyroid tissues from eight PTMC patients who underwent thyroidectomy. We also obtained eight normal thyroid tissue specimens from the thyroid lobes of the same patients for pairwise analysis. Of eight PTMC, three did not have nodal involvement and extrathyroidal extension (T1aN0). The remaining patients had lateral neck-node metastasis at initial diagnosis (T1aN1b or T3N1b) and underwent modified radical neck dissection combined with thyroidectomy. Immediately after thyroidectomy, we obtained the three pairs of 0.2 × 0.2 × 0.2-cm cubes of both cancer and normal thyroid tissue from the surgeon; the samples were snap-frozen in liquid nitrogen at the operation theater and then stored at ˗80°C.