Skip to Main Navigation
Skip to Page Content
COVID-19 is an emerging, rapidly evolving situation.

Get the latest public health information from CDC and research information from NIH.

U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Share This:
https://ntp.niehs.nih.gov/go/479

Target Organs and Levels of Evidence for TR-531

Toxicology and Carcinogenesis Studies of a Binary Mixture of 3,3',4,4',5-Pentachlorobiphenyl (PCB 126) (CASRN 57465-28-8) and 2,3',4,4',5-Pentachlorobiphenyl (PCB 118) (CASRN 31508-00-6) in Female Harlan Sprague-Dawley Rats (Gavage Studies)

Chemical (Study Title)
CASRN		 Peer Review Date Primary Uses Route/Exposure Levels Study Laboratory
TEF Evaluation (PCB Mixture; PCB 126/PCB 118)
TEFPCBMIX		 12/09/2004 One of 2 dioxin-like compounds plus mixtures being tested to determine if the TEFs for these chemicals would be predictive of rodent carcinogenicity. This mixture consists of PCB 118 (2,3',4,4',5- pentachlorobiphenyl) & PCB 126 (3,3',4,4',5- pentachlorobiphenyl) Mixtures were produced commercially before 1977 for the electric industry as dielectric insulating fluids for transformers & capacitors Gavage
Female rats only (PCB 118/PCB 126): 0, 7, 22, 72, 216, or 360 ng/kg; 50/dose		 Battelle Columbus Laboratory

Levels of Evidence

Female Rats: Clear Evidence
Type Organ/Tissue (Lesion)
Neoplastic Lesions
  • Liver: Cholangiocarcinoma 0/53 0/51 5/53 19/53 28/53 12/65 19/50 adenoma 2/53 1/51 0/53 4/53 17/53 5/65 1/50 carcinoma 0/53 0/51 0/53 0/53 1/53 0/65 0/50
  • Lung: Cystic keratinizing epithelioma 0/53 0/51 0/53 20/53 49/53 41/66 12/50
  • Oral Cavity: Gingival squamous cell carcinoma 1/53 1/51 2/53 4/53 0/53 1/66 1/50
May Have Been Related
  • Liver: Hepatocholangioma 0/53 0/51 0/53 1/53 1/53 1/65 1/50 cholangioma 0/53 0/51 0/53 1/53 0/53 0/65 0/50
Non-Neoplastic Lesions
  • Liver: hepatocyte hypertrophy; multinucleated hepatocyte; hepatocyte glandular structure; pigmentation; toxic hepatopathy; diffuse fatty change; nodular hyperplasia; centrilobular fibrosis; necrosis; oval cell hyperplasia; bile duct cyst; bile duct hyperplasia; portal fibrosis; cholangiofibrosis; eosinophilic focus; focal fatty change; centrilobular degeneration; metaplasia
  • Lung: alveolar epithelium metaplasia bronchiolar; squamous metaplasia; serosal fibrosis; keratin cyst
  • Oral cavity: gingival squamous hyperplasia
  • Thymus: atrophy; severity of atrophy
  • Thyroid gland: follicular cell hypertrophy
  • Adrenal cortex: atrophy; cytoplasmic vacuolization
  • Pancreas: acinus cytoplasmic vacuolization; chronic active artery inflammation; acinus atrophy; chronic active inflammation
  • Kidney: nephropathy; severity of nephropathy
  • Heart: cardiomyopathy; coronary artery chronic active inflammation; epicardium inflammation
  • Mandibular lymph node: hemorrhage
  • Mediastinal lymph node: hemorrhage
  • Mesenteric lymph node: hemorrhage
  • Mesentery: artery chronic active inflammation
  • Brain: hemorrhage
  • Forestomach: squamous hyperplasia
  • Spleen: lymphoid follicle atrophy
  • Nasal cavity: inflammation; respiratory epithelium hyperplasia; olfactory epithelium metaplasia