Biomaterial Database

Impaired cholesterol esterification in the plasma in patients with breast cancer. 1997

P V Subbaiah, and M Liu, and T R Witt

Department of Internal Medicine, Rush Medical College, Chicago, Illinois 60612, USA.

An important factor which determines the movement of cholesterol in and out of the cells is the free cholesterol (FC)/esterified cholesterol (EC) ratio in the plasma. Although this ratio has been shown to be increased in several types of malignancies in humans as well as experimental animals, it is not known whether such an abnormality is found in breast cancer patients. Furthermore, the reasons for such an increase in cancer patients are unknown. We studied the plasma lipid composition and the activity of lecithin-cholesterol acyltransferase (LCAT), the enzyme responsible for the formation of most of EC in human plasma, in 12 women with breast cancer and 9 age-matched control women. The plasma EC concentration was found to be significantly decreased in cancer patients, whereas the FC concentration was unchanged, leading to increased FC/EC ratios (P < 0.05). The concentration of phosphatidylcholine, the acyl donor in the LCAT reaction, was decreased significantly, whereas all other phospholipids were unaffected. The cholesterol-esterifying activity of LCAT was significantly lower in cancer patients, whether assayed with endogenous substrates (P < 0.05), or with an exogenous substrate (P < 0.01). However, another function of the enzyme, namely the lysolecithin acyltransferase activity, was increased (P < 0.02), indicating that the enzyme concentration in plasma may not be decreased. These results show that the increase in the FC/EC ratio in cancer patients is due to an impaired esterification of cholesterol by plasma LCAT, probably due to an alteration in the composition of substrate lipoproteins, or the presence of an inhibitory factor.

UI	MeSH Term	Description	Entries
D008074	Lipoproteins	Lipid-protein complexes involved in the transportation and metabolism of lipids in the body. They are spherical particles consisting of a hydrophobic core of TRIGLYCERIDES and CHOLESTEROL ESTERS surrounded by a layer of hydrophilic free CHOLESTEROL; PHOSPHOLIPIDS; and APOLIPOPROTEINS. Lipoproteins are classified by their varying buoyant density and sizes.	Circulating Lipoproteins,Lipoprotein,Lipoproteins, Circulating
D008243	1-Acylglycerophosphocholine O-Acyltransferase	An enzyme localized predominantly within the plasma membrane of lymphocytes. It catalyzes the transfer of long-chain fatty acids, preferentially unsaturated fatty acids, to lysophosphatides with the formation of 1,2-diacylglycero-3-phosphocholine and CoA. EC 2.3.1.23.	1-Acylglycerophosphocholine Acyltransferase,Acyl CoA Lysolecithin Acyltransferase,Lysolecithin Acyltransferase,Acyl-CoA-1-Acylglycero-3-Phosphocholine-O-Acyltransferase,Lysophosphatidylcholine Acyltransferase,Lysophosphatidylcholine-Palmitoyl CoA Acyltransferase,Lysophospholipid Acyltransferase,1 Acylglycerophosphocholine Acyltransferase,1 Acylglycerophosphocholine O Acyltransferase,Acyl CoA 1 Acylglycero 3 Phosphocholine O Acyltransferase,Acyltransferase, 1-Acylglycerophosphocholine,Acyltransferase, Lysolecithin,Acyltransferase, Lysophosphatidylcholine,Acyltransferase, Lysophosphatidylcholine-Palmitoyl CoA,Acyltransferase, Lysophospholipid,CoA Acyltransferase, Lysophosphatidylcholine-Palmitoyl,Lysophosphatidylcholine Palmitoyl CoA Acyltransferase,O-Acyltransferase, 1-Acylglycerophosphocholine
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D009363	Neoplasm Proteins	Proteins whose abnormal expression (gain or loss) are associated with the development, growth, or progression of NEOPLASMS. Some neoplasm proteins are tumor antigens (ANTIGENS, NEOPLASM), i.e. they induce an immune reaction to their tumor. Many neoplasm proteins have been characterized and are used as tumor markers (BIOMARKERS, TUMOR) when they are detectable in cells and body fluids as monitors for the presence or growth of tumors. Abnormal expression of ONCOGENE PROTEINS is involved in neoplastic transformation, whereas the loss of expression of TUMOR SUPPRESSOR PROTEINS is involved with the loss of growth control and progression of the neoplasm.	Proteins, Neoplasm
D001943	Breast Neoplasms	Tumors or cancer of the human BREAST.	Breast Cancer,Breast Tumors,Cancer of Breast,Breast Carcinoma,Cancer of the Breast,Human Mammary Carcinoma,Malignant Neoplasm of Breast,Malignant Tumor of Breast,Mammary Cancer,Mammary Carcinoma, Human,Mammary Neoplasm, Human,Mammary Neoplasms, Human,Neoplasms, Breast,Tumors, Breast,Breast Carcinomas,Breast Malignant Neoplasm,Breast Malignant Neoplasms,Breast Malignant Tumor,Breast Malignant Tumors,Breast Neoplasm,Breast Tumor,Cancer, Breast,Cancer, Mammary,Cancers, Mammary,Carcinoma, Breast,Carcinoma, Human Mammary,Carcinomas, Breast,Carcinomas, Human Mammary,Human Mammary Carcinomas,Human Mammary Neoplasm,Human Mammary Neoplasms,Mammary Cancers,Mammary Carcinomas, Human,Neoplasm, Breast,Neoplasm, Human Mammary,Neoplasms, Human Mammary,Tumor, Breast
D002784	Cholesterol	The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.	Epicholesterol
D004951	Esterification	The process of converting an acid into an alkyl or aryl derivative. Most frequently the process consists of the reaction of an acid with an alcohol in the presence of a trace of mineral acid as catalyst or the reaction of an acyl chloride with an alcohol. Esterification can also be accomplished by enzymatic processes.	Esterifications
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults