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Antonio de las Morenas

Publications and source records attributed to Antonio de las Morenas.

5 recordsLinked to original sources
PubMed2005

Allele imbalance, or loss of heterozygosity, in normal breast epithelium of sporadic breast cancer cases and BRCA1 gene mutation carriers is increased compared with reduction mammoplasty tissues.

PURPOSE: Normal-appearing breast epithelium can contain genetic abnormalities, including allele imbalance (AI), also referred to as loss of heterozygosity. Whether abnormalities are associated with cancer or cancer risk is unknown. PATIENTS AND METHODS: We performed a miniallelotype, using 20 microsatellites, on each of 460 histologically normal, microdissected breast terminal ducto-lobular units (TDLUs) from three groups of women: sporadic breast cancer patients (SP; n = 18), BRCA1 gene mutation carriers (BRCA1; n = 16), and controls undergoing reduction mammoplasty (RM; n = 18). We analyzed the results using Fisher's exact tests, logistic regression, and generalized estimating equations. RESULTS: AI was increased three-fold in SP and BRCA1 groups compared with RM. Both the number of TDLUs with AI increased (eight [5%] of 162 in the RM group compared with 24 [15%] of 162 in the SP and 22 [16%] of 136 in the BRCA1 groups; P = .0150), and the proportion of patients with AI increased (five [28%] of 18 in the RM group compared with 15 [83%] of 18 in the SP and 13 [81%] of 16 in the BRCA1 groups; P = .0007). The adjusted odds ratios (OR) for AI in TDLU increased in SP (OR = 15.5) and BRCA1 (OR = 13.7) patients compared with RM (P = .0025). This result was particularly evident on chromosome 17q (P = .0393), where more AI was seen in BRCA1 (OR = 12.4) than in SP (OR = 4.9) patients or RM controls. CONCLUSION: Increased prevalence of AI in normal-appearing epithelium is associated with breast cancer and increased breast cancer risk. The increased prevalence may reflect dysregulation, even in normal-appearing epithelium, of genomic processes contributing to cancer development. The clinical significance of genetic alterations in the subset of controls remains to be determined.

Adult↗
PubMed2004

Quantitative DNA fingerprinting may distinguish new primary breast cancer from disease recurrence.

PURPOSE: Approximately 10% of women with breast cancer develop a second breast tumor, either a new primary or a recurrence. Differentiating between these entities using standard clinical and pathologic criteria remains challenging. Ambiguous cases arise, and misclassifications may occur. We investigated whether quantitative DNA fingerprinting, based on allele imbalance (AI) or loss of heterozygosity (LOH), could evaluate clonality and distinguish second primary breast cancer from recurrence. METHODS: We developed a scoring system based on the AI/LOH fingerprints of 20 independent breast tumors and generated a decision rule to classify any breast tumor pair as related or unrelated. We validated this approach on eight related tumors (cancers and synchronous positive lymph nodes). Finally, we analyzed paired tumors from 13 women (bilateral cancers, primary tumors and contralateral positive axillary lymph nodes, or two ipsilateral tumors). Each pair's genetic classification was compared with their clinical diagnosis and outcome. RESULTS: Each independent cancer had a unique fingerprint. Every tumor pair's relationship was quantifiable. Six of eight related tumor pairs were genetically classified correctly, two were indeterminate, and none were misclassified. Among the 13 women with two cancers, four of five clinically indeterminate pairs could be classified genetically. In three of 13 women, the pair's classification contradicted the clinical diagnosis. These women had bilateral cancers genetically classified as related and disease progression. This challenges the paradigm that bilateral cancers represent independent tumors. Overall, women with tumors genetically classified as related had poorer outcomes. CONCLUSION: Quantitative AI/LOH fingerprinting is a potentially valuable tool to improve diagnosis and optimize treatment for the growing number of second breast malignancies.

Alleles↗
PubMed2003

Loss of heterozygosity in serial plasma DNA samples during follow-up of women with breast cancer.

We evaluated the potential utility of occult circulating tumor DNA as a molecular marker of disease in subjects previously diagnosed with breast cancer. Using 24 microsatellite markers located at sites of frequent loss of heterozygosity (LOH) or allele imbalance in breast cancer, we analyzed DNA from 16 primary tumors (Stage IIA or more advanced) and 30 longitudinally collected plasma specimens. Clinical data at the time of plasma collection were obtained. All 16 tumors were characterized by an individual pattern of LOH. LOH was detected in 12 of 30 (40%) plasma samples, taken from 8 of 14 (57%) subjects. However, the number of LOH in plasma was small (n = 15), and the mean proportion of LOH was much lower than in the tumors (0.05 vs. 0.52). Although infrequent, 12 of 15 (80%) plasma LOH were concordant with abnormalities in the paired tumors, and the mean percent LOH was higher than in normal plasmas, suggesting that they were authentic tumor-derived abnormalities. We found, despite this, no association, between plasma LOH and tumor stage or clinical status at time of blood collection (i.e., LOH was as common in subjects with no evident disease as in those with evident disease). In addition, detection of LOH was not consistent between serial samples from 5 of 11 subjects (45%), despite stable clinical conditions. No association with clinical outcome was evident, although the sample size was small. Microsatellite instability in plasma was infrequent, nonconcordant with paired tumor and inconsistent in serial samples. This pilot study suggests that identifying tumor-specific LOH in the plasma of breast cancer subjects may not be useful for detecting occult metastases or for monitoring disease. Other detection techniques may be more promising, but circulating tumor DNA may not be a sufficiently accurate reflection of breast cancer clinical status or tumor activity.

Adenocarcinoma↗
PubMed2002

Loss of heterozygosity or allele imbalance in histologically normal breast epithelium is distinct from loss of heterozygosity or allele imbalance in co-existing carcinomas.

To better understand early steps in human breast carcinogenesis, we examined allele imbalance or loss of heterozygosity (LOH), in co-existing normal-appearing breast epithelium and cancers. We microdissected a total of 173 histologically normal ducts or terminal ductolobular units (TDLUs) and malignant epithelial samples from 18 breast cancer cases, and examined their DNA for LOH at 21 microsatellite markers on 10 chromosome arms. Fourteen of 109 (13%) normal ducts/TDLUs, from 8 of 18 (44%) cases, contained LOH. The location of these 14 ducts/TDLUs appeared unrelated to distance from the cancer. LOH in normal-appearing epithelium involved only single markers, whereas LOH in cancers commonly encompassed all informative markers on a chromosome arm. In only 1 of 14 (7%) ducts/TDLUs with LOH, was the same LOH seen in the co-existing cancer. Global differences in LOH per arm in normal-appearing tissue were not demonstrated, but less LOH was seen at 11q and 17p than at 1q (P = 0.002), 16q (P = 0.01), and possibly 17q (P = 0.06). These results indicate that in a large fraction of women with breast cancer, histologically normal breast epithelium harbors occult aberrant clones. Individual clones rarely are precursors of co-existing cancers. However, they might constitute a reservoir from which proliferative lesions or second cancers develop once additional genetic abnormalities occur, they could contribute to intratumoral genetic heterogeneity, and they are consistent with a role for genetic instability early in tumorigenesis.

Allelic Imbalance↗