Loss of heterozygosity analyses of asynchronous lesions of ductal carcinoma in situ and invasive ductal carcinoma of the human breast.
BACKGROUND
Ductal carcinoma in situ (DCIS) of the breast is known to possess characteristics of the pre-invasive stage of breast cancer and is the precursor to invasive ductal carcinoma (IDC). However, the natural history of the progression from DCIS to IDC remains unknown at the molecular level.


METHODS
We investigated the loss of heterozygosities (LOHs) in tumors of seven patients with a history of breast biopsy. The seven specimens were diagnosed as DCIS on histopathological re-examination. These patients were diagnosed with ipsilateral breast cancer a few years after biopsy. We used thirteen selected microsatellite markers that were mapped to and/or very close to the tumor suppressor genes or regions with frequent LOHs in breast cancer. DNA isolated from microdissected formalin-fixed, paraffin-embedded tissues was subjected to a PCR-LOH analysis for these chromosome loci, and the pattern of LOHs was compared between the two asynchronous lesions for the seven cases.


RESULTS
In all patients except one, the LOHs were concordant at 91% as the informative chromosome loci in cases 1 to 6 were 56, and the concordance in LOH pattern between DCIS and IDC was detected at 50 loci. The LOHs had accumulated in accordance with the tumor progression from DCIS to IDC. The recurrent lesion occurred at or near the site of the primary biopsy and had similar or identical histopathologic features.


CONCLUSIONS
These recurrences observed were probably residual disease rather than true recurrences. Our results suggest the following: (i) genetic alternations accumulate during cancer progression from DCIS to IDC, (ii) DCIS is a lesion that has a high risk of developing invasive transformation and (iii) after approximately 5 years without treatment, DCIS may develop into IDC.
Amari
Masakazu
M
Division of Surgical Oncology, Department of Pathology, Tohoku University School of Medicine, Sendai, Japan.
Moriya
Takuya
T
Ishida
Takanori
T
Harada
Yuko
Y
Ohnuki
Koji
K
Takeda
Motohiro
M
Sasano
Hironobu
H
Horii
Akira
A
Ohuchi
Noriaki
N
D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000235:genetics* / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000235:genetics* / Q000473:pathology; D005260:Female; D016147:Genes, Tumor Suppressor; D006801:Humans; D019656:Loss of Heterozygosity; D018895:Microsatellite Repeats; D016612:Paraffin Embedding