RET and thyroid gland papillary carcinoma: For example: (i) 3D fluorescent in situ hybridization analysis has shown that mixed-lineage leukemia (MLL) and its translocation partners, eleven-to-nineteen leukemia proteins (ENL) and AML-fused genes from chromosome 4 (AF4), are adjacently located in interphase nuclei [26]; (ii) BCR and ABL loci are close to one another in CD34+ bone marrow cell [27]; and (iii) RET and PTC1 loci involved in RET–PTC1 fusion in papillary thyroid cancer were found to be closer to one another in thyroid cells than in lymphocytes [28,30,31].