https://ntp.niehs.nih.gov/go/n544616

Target Organs and Levels of Evidence for TR-606

Toxicology and Carcinogenesis Studies of α-Pinene (CASRN 80-56-8) Administered by Inhalation to Sprague Dawley (Hsd:Sprague Dawley SD) Rats, B6C3F1/N Mice, and CD-1 Mice

Chemical (Study Title)
CASRN		Peer Review DateRoute/Exposure LevelsStudy Laboratory
α-Pinene
80-56-8		06/01/2025Inhalation 
Rats: 0, 50, 100, or 200 ppm; Mice: 0, 100, 200, or 400 ppm
  • RTI International Laboratory
  • Battelle Columbus Laboratory

Levels of Evidence

Male Rats: Some Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Urinary bladder: papilloma (0/50, 0/50, 0/50, 3/50)
Non-Neoplastic Lesions
  • Testis: germinal epithelium, degeneration (includes bilateral); germinal epithelium, degeneration or atrophy (combined, includes bilateral)
  • Epididymis: hypospermia (includes bilateral)
  • Adrenal gland: medulla, hyperplasia, focal (includes bilateral)
  • Liver: bile duct, hyperplasia
Female Rats: Clear Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Mammary gland: adenocarcinoma (5/49, 7/50, 11/50, 25/50); adenoma or adenocarcinoma (combined) (6/49, 7/50, 15/50, 25/50)
  • Uterus: adenocarcinoma (1/50, 7/49, 3/50, 4/49); squamous cell carcinoma (0/50, 0/49, 1/50, 3/49); squamous cell papilloma, squamous cell carcinoma, adenoma or adenocarcinoma (combined) (1/50, 7/49, 4/50, 6/49); polyp, stromal (5/50, 2/49, 4/50, 8/49)
     
Non-Neoplastic Lesions
  • Uterus: hyperplasia, atypical; endometrium, hyperplasia, stromal
  • Bone marrow: hypercellularity
  • Spleen: extramedullary hematopoiesis, increased
Male Mice: Clear Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Harderian gland: adenoma (includes bilateral) (6/50, 9/50, 11/50, 16/50); adenocarcinoma (includes bilateral) (0/50, 1/50, 3/50, 7/50); adenoma or adenocarcinoma (combined) (6/50, 9/50, 14/50, 23/50)
  • Liver: hepatocellular adenoma (includes multiple) (23/50, 26/50, 31/49, 33/50); hepatocellular carcinoma (includes multiple) (18/50, 26/50, 17/49, 36/50); hepatocellular adenoma or hepatocellular carcinoma (combined, includes multiple) (33/50, 40/50, 40/49, 46/50)
  • Lung: alveolar/bronchiolar adenoma (includes multiple) (5/50, 8/50, 10/50, 18/50); alveolar/bronchiolar adenoma or alveolar/bronchiolar carcinoma (combined, includes multiple) (14/50, 14/50, 21/50, 26/50)
  • Urinary bladder: papilloma (0/48, 0/43, 0/48, 3/45)
  • Stomach, forestomach: papilloma (0/49, 0/49, 2/50, 3/48)
     
Non-Neoplastic Lesions
  • Liver: multinucleated hepatocyte; basophilic focus; necrosis
  • Lung: alveolar/bronchiolar, epithelium, hyperplasia
  • Urinary bladder: urothelium, hyperplasia; infiltration cellular, lymphocyte; inflammation, suppurative
  • Testis: germinal epithelium, degeneration (includes bilateral); germinal epithelium, atrophy (includes bilateral); germinal epithelium, degeneration or atrophy (combined, includes bilateral)
  • Epididymis: duct, exfoliated germ cell (includes bilateral)
Female Mice: Clear Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Harderian gland: adenoma (includes bilateral) (3/50, 6/49, 11/40, 16/50); adenocarcinoma (includes bilateral) (1/50, 2/49, 3/40, 6/50); adenoma or adenocarcinoma (combined) (4/50, 8/49, 13/40, 22/50)
  • Liver: hepatocellular adenoma (includes multiple) (6/50, 15/50, 20/38, 28/50); hepatocellular carcinoma (includes multiple) (7/50, 14/50, 11/38, 20/50); hepatocellular adenoma or hepatocellular carcinoma (combined, includes multiple) (12/50, 27/50, 24/38, 39/50)
  • Lung: alveolar/bronchiolar adenoma (includes multiple) (2/50, 8/50, 9/39, 17/50); alveolar/bronchiolar carcinoma (includes multiple) (1/50, 2/50, 6/39, 23/50); alveolar/bronchiolar adenoma or alveolar/bronchiolar carcinoma (combined, includes multiple) (3/50, 10/50, 15/39, 37/50)
  • Mammary gland: adenocarcinoma (0/48, 0/46, 0/40, 5/48); adenoma or adenocarcinoma (combined) (0/48, 0/46, 1/40, 5/48)
  • Ovary: granulosa cell tumor, benign, malignant (combined) (0/48, 3/49, 2/36, 5/46); tubulostromal adenoma (0/48, 0/49, 1/36, 7/46)
  • Stomach, forestomach: squamous cell carcinoma (0/49, 0/49, 0/38, 2/49)
Non-Neoplastic Lesions
  • Lung: alveolar/bronchiolar, epithelium, hyperplasia
  • Urinary bladder: urothelium, hyperplasia
  • Ovary: hyperplasia, tubulostromal (includes bilateral)
  • Stomach, forestomach: epithelium, hyperplasia, focal