Mutations of the adenomatous polyposis coli gene in sporadic thyroid neoplasms.

Abstract

Several epidemiological studies have demonstrated an association between familial adenomatous polyposis coli (FAP) and thyroid neoplasms. Predisposition to FAP is conferred by mutations in the APC gene, located on chromosome 5q21. Somatic mutations of APC are also observed in about 60% of sporadic colorectal adenomas and carcinomas, suggesting that disruption of this putative tumor suppressor gene may play a role in both familial as well as acquired colorectal tumorigenesis. The APC gene is expressed in normal human thyroid, thyroid adenomas, and differentiated carcinoma tissues as well as in four clonal human thyroid carcinoma cell lines, as demonstrated by reverse transcriptase-polymerase chain reaction of a 388-base APC messenger ribonucleic acid fragment spanning exons 14 and 15, followed by hybridization to an exon 15-specific complementary DNA probe. Eighty human thyroid neoplasms were examined for loss of heterozygosity of the APC locus, using primers flanking a hypervariable dinucleotide (CA) repeat (CB26) immediately adjacent to the APC gene. Of 71% informative samples, 2 showed allelic loss: a follicular adenoma (FA) and a nodule from a multinodular goiter (MNG). The DNA of 83 benign and malignant thyroid neoplasms and 4 thyroid carcinoma cell lines was examined for mutations within a 1200-basepair stretch of exon 15 by single strand conformation polymorphism. Five sets of overlapping primers were used for PCR. The anaplastic thyroid carcinoma cell line (ARO) had 1 APC allele with an adenine insertion at codon 1556 (ACTA to AACTA), leading to a premature stop codon at 1558. An anaplastic carcinoma had a mutation of codon 1346 (TCA-CCA; Ser to Pro). In summary, the APC gene is expressed in normal and neoplastic human thyroid tissue and is a target for inactivating mutations in some thyroid tumors.

BRAFV599EMutation Is the Leading Genetic Event in Adult Sporadic Papillary Thyroid Carcinomas

“…Mutational analysis was then performed on the obtained PCR products by singlestranded conformational polymorphism (SSCP) screening. SSCP analysis was conducted using a modification of a method previously reported (30). In detail, 5 l PCR product was mixed with 25 l DNA gel-loading buffer (95% formamide, 20 mm NaOH, 20 mm EDTA, 0.05% bromophenol blue, 0.05% xylene cyanol), denatured by incubating at 95 C for 5 min, placed on ice, and loaded onto a 0.5ϫ mutation detection enhancement gel (MDE gel solution, Cambrex, Rockland, ME) containing 10% glycerol.…”

Involvement of Protein Kinase Cε (PKCε) in Thyroid Cell Death

“…The human thyroid carcinoma cell lines NPA, ARO, and WRO were a gift of G. Juilliard (UCLA), and propagated in RPMI 1640 medium containing 10% fetal calf serum, non-essential amino acids (Irvine Scientific, Irvine, CA), glutamine (286 mg/liter), penicillin, and streptomycin (Life Technologies, Inc., Gaithersburg, MD), as described (19). PCCL3 cells were propagated in H6 medium, which consisted of Coons modification of Ham's F-12 media (Irvine Scientific, Irvine, CA) containing 5% fetal calf serum, glutamine (286 mg/l), somatostatin (10 ng/ml), glycyl-L-histidyl-L-lysin acetate (10 ng/ml), transferrin (5 g/ ml), hydrocortisone (10 nM), insulin (10 g/ml), thyroid stimulating hormone (TSH, 10 mIU/ml), penicillin, and streptomycin, as described (20).…”

Genetic and epigenetic alterations of the APC gene in malignant melanoma

“…Germline APC mutations are responsible for familial adenomatous polyposis, an autosomaldominant precancerous condition characterized by the appearance of multiple adenomatous polyps of the colorectum, and acquired APC mutations have been found in the majority of sporadic colorectal cancers (Fodde, 2002). A more widespread role of APC in human cancer has been suggested by the demonstration of APC mutations in hepatoblastomas and in gastric, pancreatic, thyroid, breast, and ovarian cancers, albeit at rates significantly lower than in colorectal tumours (Horii et al, 1992a, b;Zeki et al, 1994;Oda et al, 1996;Furuuchi et al, 2000;Wu et al, 2001). Moreover, transcriptional silencing of APC by promoter hypermethylation, a potential alternative mechanism of gene inactivation, has been found in a variety of human malignancies, with particularly high rates in oesophageal, gastric, breast, lung, and endometrial cancers (Hiltunen et al, 1997;Esteller et al, 2000;Kawakami et al, 2000;Tsuchiya et al, 2000;Virmani et al, 2001;Moreno-Bueno et al, 2002;Usadel et al, 2002).…”