Table 2.

Expression and distribution of human-specific biomarkers in normal tissue.

Cell type	Ku80	hMito	Alu
Nervous system
Neurons	+++	++	+++
Glial cells	+++	+	+++
Endocrine system
Thyrocytes	+++	++	+++
Respiratory system
Pneumocytes type I	+++	−	+++
Pneumocytes type II	+++	+++	+++
Digestive tract
Esophageal epithelium	+++	+++	+++
Fundic glands	+++	+++	+++
Enterocytes	+++	+++	+++
Goblet cells	+++	+++	+++
Lieberkuhn's glands	+++	+++	+++
Digestive organs
Liver:
Hepatocytes	+++	+++	+++
Bile duct	+++	+++	+++
Pancreas:
Islets of Langerhans	+++	+	+++
Acinar cells	+++	++	+++
Immune system
Spleen, lymph node, tonsil:
Lymphocytes	+++	++	+++
Hematopoietic cells	++	+++	+++
Urinary tract
Kidney:
Proximal tubule	+++	+++	+++
Loop of Henle	+++	+++	+++
Collecting duct	+++	++	+++
Connective tissue
Fibroblasts	++	+	+++
Chondrocytes	+++	+	+++
Osteoblasts	+++	+	+++
Osteocytes	+++	+	+++
Muscle and cardiovascular system
Smooth muscle	++	++	+++
Skeletal muscle	+++	++	+++
Cardiomyocytes	+++	++	+++
Endothelial cells	+++	+	+++
Reproductive system
Testis:
Spermatogonia	+++	++	+++
Spermatid	+++	++	+++
Spermatozoa	−	−	+++
Leydig cells	+++	+++	+++
Prostate:
Epithelial cells	+++	++	+++
Uterus:
Myometrium	+++	++	+++
Endometrial glands	+++	+++	+++
Mammary glands	+++	+++	+++
Placenta:
Cytotrophoblast	+++	++	+++
Syncitiotrophoblast	+++	+++	+++

Labeling for Ku80 and Alu was mostly confined to the nucleus unlike cytoplasm staining for hMito. Immunoreactivity was assessed by semi-quantitative scoring.

−: 0%; +: <30%; ++: 30–60%; +++: >60% of immunoreactive cells throughout the whole organ; hMito: Human mitochondria.