Triplet repeat instability correlates with dinucleotide instability in primary breast cancer.

The expansion of triplet repeat microsatellite sequences is the molecular correlate of anticipation in a number of rare Mendelian neurodegenerative disorders. This finding prompted us to study these sequences in primary breast cancer in which there is evidence of genetic anticipation. We used a PCR/silver stain method to determine whether triplet-repeat instability (TRI) was present in DNA from malignant breast tumors, and analyzed microsatellite instability (MSI) in triplets SCA1, SCA2, SCA3, SCA6, HD, DRPLA and X25-GAA.

Loss of hMSH2 expression in primary breast cancer with p53 alterations.

Inactivation of DNA mismatch repair genes (MRG) is a recently described pathway of cancer development and progression resulting in genetic instability. Germline mutations in MRG have been studied predominantly in patients with hereditary non-polyposis colorectal cancer (HNPCC) where it is associated with microsatellite instability (MSI). The expression of MRG in primary breast cancer is still largely unexplored.

p53 expression is decreased in primary breast carcinomas with microsatellite instability.

p53 and p185 expression in primary breast cancer with microsatellite instability (MSI) is still largely unexplored. To investigate the relationship between these oncoproteins and the pathways of genomic instability, we examined 52 primary invasive breast cancers stratified by the presence and absence of MSI. We determined the status of eight microsatellite loci using radioactive and silver staining methods, and evaluated the immunohistochemical expression of p53 and p185 in a consecutive series of Italian cancer patients characterized by clinical-pathological and biological parameters.

Microsatellite instability is correlated with lymph node-positive breast cancer.

We analyzed 81 cases of primary breast carcinoma and 7 cases of fibroadenoma for microsatellite instability at eight loci. Twenty-seven cases (33.3%) manifested aberrant microsatellite alleles: 7 (8.

Microsatellite instability and pathological aspects of breast cancer.

Genomic instability plays a key role in hereditary nonpolyposis colorectal cancer and in a significant sub-set of non-hereditary colorectal tumors. Recent evidence suggests that microsatellite instability also occurs in various sub-sets of common, non-hereditary forms of extra-colorectal carcinoma. To investigate the role of microsatellite instability in breast cancer, and to correlate this type of alteration with clinico-pathological characteristics, including tumor proliferative activity, we analyzed the status of 8 different microsatellite loci in 28 cases of primary mammary carcinoma.