p53 mutations and c-erbB-2 amplification in intraductal and invasive breast carcinomas of high histologic grade

Ductal Carcinoma In Situ Biology, Biomarkers, and Diagnosis

Ductal carcinoma in situ (DCIS) is an often-diagnosed breast disease and a known, non-obligate, precursor to invasive breast carcinoma. In this review, we explore the clinical and pathological features of DCIS, fundamental elements of DCIS biology including gene expression and genetic events, the relationship of DCIS with recurrence and invasive breast cancer, and the interaction of DCIS with the microenvironment. We also survey how these various elements are being used to solve the clinical conundrum of how to optimally treat a disease that has potential to progress, and yet is also likely over-treated in a significant proportion of cases.

p53 and Breast Cancer

Inactivation of the p53 tumor suppressor gene is one of the commonest genetic changes identified in human breast cancer. In this review, the structure and function of the p53 gene and its protein products will be discussed, with particular reference to p53 alterations that contribute to carcinogenesis. The frequency and pattern of p53 alterations in breast cancer will be outlined, laboratory methods for their detection briefly summarized, and the potential use of p53 as a prognostic and predictive marker discussed.

A Cohort Study of p53 Mutations and Protein Accumulation in Benign Breast Tissue and Subsequent Breast Cancer Risk

Mutations in the p53 tumor suppressor gene and accumulation of its protein in breast tissue are thought to play a role in breast carcinogenesis. However, few studies have prospectively investigated the association of p53 immunopositivity and/or p53 alterations in women with benign breast disease in relation to the subsequent risk of invasive breast cancer. We carried out a case-control study nested within a large cohort of women biopsied for benign breast disease in order to address this question. After exclusions, 491 breast cancer cases and 471 controls were available for analysis. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI). Neither p53 immunopositivity nor genetic alterations in p53 (either missense mutations or polymorphisms) was associated with altered risk of subsequent breast cancer. However, the combination of both p53 immunopositivity and any p53 nucleotide change was associated with an approximate 5-fold nonsignificant increase in risk (adjusted OR 4.79, 95% CI 0.28-82.31) but the confidence intervals were extremely wide. Our findings raise the possibility that the combination of p53 protein accumulation and the presence of genetic alterations may identify a group at increased risk of breast cancer.

TP53 genetic alterations in Arab breast cancer patients: Novel mutations, pattern and distribution

Breast cancer remains a worldwide public health concern. The incidence and mortality of breast cancer varies significantly in ethnically and geographically distinct populations. In the Kingdom of Saudi Arabia (KSA) breast cancer has shown an increase in incidence and is characterized by early onset and aggressiveness. The tumor suppressor TP53 gene is a crucial genetic factor that plays a significant role in breast carcinogenesis. Furthermore, studies have shown a correlation between certain p53 mutations and response to therapy in breast cancer. In the present study, TP53 mutations were identified by direct sequencing of the gene (exons 4-9) from 119 breast cancer tissues. The prevalence of TP53 mutations in Arab breast cancer patients living in the KSA is among the highest in the world (40%). Notably, 73% of the patients whose tumors harbored p53 mutations were less than 50 years of age. Furthermore, for the first time, we identified 7 novel mutations and 16 mutations in breast cancer tissues. Notably, all the novel point mutations were found in exon 4, wherein 29% of the mutations were localized. Furthermore, an excess of G:C→A:T transitions (49%) at non-CpG sites was noted, suggesting exposure to particular environmental carcinogens such as N-nitroso compounds. The results indicate that the TP53 gene plays a significant role in breast carcinogenesis and the early onset of the disease among Arab female individuals.

Gene and chromosomal alterations in sporadic breast cancer: correlation with histopathological features and implications for genesis and progression

A number of gene and chromosome alterations have been identified in sporadic breast carcinomas, and their clinical implications have been investigated. Changes in proto-oncogenes and tumor-suppressor genes, e.g., HER2, p53, and E-cadherin, and various numerical and structural chromosome alterations are strongly correlated with histological type and grade in breast carcinomas. The amount of information on these alterations has been dramatically increased by the introduction of high-throughput molecular cytogenetic approaches. In the near future, breast cancers will be classified into specific groups according to their profile of gene and chromosome alterations, allowing more effective personalized therapies targeting the associated molecular pathways.

The role of HER2 in early breast cancer metastasis and the origins of resistance to HER2-targeted therapies

The HER2 gene encodes the receptor tyrosine kinase HER2 and is often over-expressed or amplified in breast cancer. Up-regulation of HER2 contributes to tumor progression. Many aspects of tumor growth are favorably affected through activation of HER2 signaling. Indeed, HER2 plays a role in increasing proliferation and survival of the primary tumor and distant lesions which upon completion of full transformation cause metastases. P185(HER2/neu) receptors and signaling from them and associated molecules increase motility of both intravasating and extravasating cells, decrease apoptosis, enhance signaling interactions with the microenvironment, regulate adhesion, as well as a multitude of other functions. Recent experimental and clinical evidence supports the view that the spread of incompletely transformed cells occurs at a very early stage in tumor progression. This review concerns the identification and characterization of HER2, the evolution of the metastasis model, and the more recent cancer stem cell model. In particular, we review the evidence for an emerging mechanism of HER2(+) breast cancer progression, whereby the untransformed HER2-expressing cell shows characteristics of stem/progenitor cell, metastasizes, and then completes its final transformation at the secondary site.

Expression of centromere protein F (CENP-F) associated with higher FDG uptake on PET/CT, detected by cDNA microarray, predicts high-risk patients with primary breast cancer

BACKGROUND

Higher standardized uptake value (SUV) detected by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) correlates with proliferation of primary breast cancer. The purpose of this study is to identify specific molecules upregulated in primary breast cancers with a high SUV and to examine their clinical significance.

METHODS

We compared mRNA expression profiles between 14 tumors with low SUVs and 24 tumors with high SUVs by cDNA microarray. We identified centromere protein F (CENP-F) and CDC6 were upregulated in tumors with high SUVs. RT-PCR and immunohistochemical analyses were performed to validate these data. Clinical implication of CENP-F and CDC6 was examined for 253 archival breast cancers by the tissue microarray.

RESULTS

The relative ratios of CENP-F and CDC6 expression levels to beta-actin were confirmed to be significantly higher in high SUV tumors than in low SUV tumors (p = 0.027 and 0.025, respectively) by RT-PCR. In immunohistochemical analysis of 47 node-negative tumors, the CENP-F expression was significantly higher in the high SUV tumors (74%) than the low SUV tumors (45%) (p = 0.04), but membranous and cytoplasmic CDC6 expressions did not significantly differ between both groups (p = 0.9 each). By the tissue microarray, CENP-F (HR = 2.94) as well as tumor size (HR = 4.49), nodal positivity (HR = 4.1), and Ki67 (HR = 2.05) showed independent impact on the patients' prognosis.

CONCLUSION

High CENP-F expression, correlated with high SUV, was the prognostic indicators of primary breast cancer. Tumoral SUV levels may serve as a pretherapeutic indicator of aggressiveness of breast cancer.

Precursors and preinvasive lesions of the breast: the role of molecular prognostic markers in the diagnostic and therapeutic dilemma

Precursors and preinvasive lesions of the breast include atypical ductal hyperplasia (ADH), ductal carcinoma in situ (DCIS), and lobular neoplasia (LN). There is a significant debate regarding the classification, diagnosis, prognosis and management of these lesions. This review article describes the current theories regarding the pathogenesis and molecular evolution of these lesions. It reviews the implication of a variety of molecules in the continuum of breast lesions: estrogen receptors (ER-alpha and ER-beta), c-erb-B2 (Her2/neu), p53, Ki-67, bcl-2, E-cadherin, transforming growth factor-beta (TGF-beta), p27 (Kip1), p16 (INK4a), p21 (Waf1), vascular endothelial growth factor (VEGF). With respect to the aforementioned molecules, this article reviews their pathophysiological importance, and puts the stress on whether they confer additional risk for invasive breast cancer or not. This knowledge has the potential to be of importance in the therapeutic decisions presenting in the common clinical practice.

Over-expression of c-erbB-2 correlates with nuclear morphometry and prognosis in breast carcinoma in Asian women

AIM

We aimed to investigate the immunohistochemical expression of c-erbB-2 in invasive breast carcinoma in Asian women and its correlations with clinicopathological parameters and nuclear morphometry. Patients were followed up for disease relapse and overall survival, and the data were reviewed in conjunction with c-erbB-2 over-expression.

METHODS

Paraffin sections from 321 invasive breast cancers were immunohistochemically stained with anti-human c-erbB-2 antibody using the streptavidin-biotin technique.

RESULTS

c-erbB-2 was over-expressed in 110 (34.3%) cases, with an inverse correlation with oestrogen receptor (ER) and progesterone receptor (PR) status (p=0.0001) and a positive correlation with histological grade (p=0.017). Nuclear morphometry in 96 cases revealed rounder nuclei in c-erbB-2 negative tumours (p=0.0322) when compared with c-erbB-2 positive tumours. Among c-erbB-2 positive cases, malignant cells of histological grade 3 tumours revealed larger nuclear area and perimeter than grade 1 and 2 cases (p=0.0095, p=0.03, respectively) while increasing tumour size correlated with greater nuclear perimeter (p=0.046). c-erbB-2 positivity was significantly associated with poor survival when all patients were included in the analysis (p=0.0166) and for subsets of node positive, histological grade 1 and 2, and ER positive tumours, and in women aged over 50 years (p=0.0047, p=0.0367, p=0.0092, p=0.0096, respectively).

CONCLUSIONS

c-erbB-2 was independently prognostic when histological grade, nodal and ER status were considered. Our results show that c-erbB-2 over-expression correlates with poor histological grade and negative ER/PR status, and predicts poor overall survival in Asian women with breast cancer.

BRCA1 and TP53 mutation spectrum of breast carcinoma in an ethnic population of Kashmir, an emerging high-risk area

Breast cancer shows geographical variation in its incidence, even within areas of ethnic homogeneity. Kashmir valley (India), over past few years, witnesses an increase in incidence and occurrence of familial, early onset, and male breast cancer in its unexplored ethnic population. Here, we make a preliminary attempt to estimate the nature and frequency of BRCA1 and TP53 gene mutations of breast cancer patients from Kashmir. PCR-SSCP analysis followed by direct sequencing revealed the presence of only two germline intronic variations (c.199+67T>C and c.5396+187T>C) in BRCA1 gene in only 5.26% (2/38) patients while as 44% (11/25) of sporadic breast cancer patients harboured significant amount of somatic mutations in TP53 (p=0.0074; OR=0.053). The 17 mutations found in TP53 in 11 patients, comprised of 13 substitutions [11 single-base (9 transitions+2 transversions), 1 double-base and 1 complex] and four insertions. The 11 substitutions represent missense mutations, leading to aminoacid substitution while as rest two were silent mutations. The four insertions represented three frame-shifts and one non-sense mutation. The mutation effect data was found to be significant (p=0.0002). Significant amount of mutations were found in exon 6 (p=0.04; OR=0.273) and a combination of exons 6 and 7 (p=0.0145; OR=14.22) of TP53. Comparison of mutation profile with other ethnic populations and regions reflected both differences and similarities indicating co-exposure to a unique set of risk factors. The differences could be due to exposure to particular environmental carcinogens; different lifestyle, reproductive pattern; dietary or cultural practices of Kashmiri women that need further investigations. The infrequent presence of germline BRCA1 mutations in our study agree with the idea that a great proportion of moderate risk breast cancer population could be due to the susceptibility genes distinct from BRCA1. However, high frequency of somatic TP53 gene mutations implicates TP53 as a predominant factor for breast carcinogenesis in moderate risk ethnic Kashmiri population. The study also suggests TP53 as a potential molecular marker and prognostic tool, at least in a subset of sporadic breast tumors.

Early breast cancer

Breast cancer remains a common disease throughout the world. Here we review new knowledge about early breast cancer obtained during the past 5 years. The prognosis of early breast cancer is generally favorable. Especially, ductal carcinoma in situ has been regarded as a non-life-threatening disease. Therefore, early diagnosis and early onset of the treatment has been important. Early age at menarche, late age at first birth, and late age at menopause are related to breast cancer risk. Examination by mammography and ultrasonography is still the most effective means of detection for premenopausal and postmenopausal women, respectively. Additionally, there have been important advances in MRI, sentinel lymph node biopsy, breast-conserving surgery, partial breast irradiation, neoadjuvant systemic therapy, and adjuvant systemic therapy. Another approach to keeping the disease under control is the elucidation of breast cancer's molecular biological features. Assessment of potential molecular targets can lead to early diagnosis and molecular targeted treatment.

Biology of Ductal Carcinoma in Situ Classification Based on Biologic Potential

Incidence of ductal carcinoma in situ (DCIS) has increased significantly during the last decade, comprising almost 20% of all breast cancers diagnosed today. DCIS is composed of malignant breast duct epithelial cells that have clonally proliferated and accumulated within the mammary duct lumen. It comprises a group of heterogeneous tumors with varying biologic behavior rendering its classification and management challenging. By definition, DCIS does not invade through the basement membrane; it is a preinvasive malignancy and systemic disease is nonexistent. The basis of treatment is to prevent progression into an invasive cancer such as ductal carcinoma. Most current DCIS classification schemes do not predict its potential to progress to invasive disease. In this review the natural history of DCIS, as it relates to its biologic potential to progress to invasive disease, is summarized, and a broad classification system that may provide a guideline for patient management is proposed.

Synchronous liver metastases of intracystic papillary carcinoma with invasion of the breast

A rare case of intracystic papillary carcinoma (IPC) with invasion had synchronous metastases to the liver at presentation. A 57-year-old postmenopausal woman noticed a right breast tumor 7 months prior to admission. Mammography showed an oval mass measuring 3.1 cm in diameter with no calcification, and ultrasonography showed an intracystic tumor with a papillary growth pattern. Fine-needle aspiration cytology revealed adenocarcinoma. Excisional biopsy revealed intracystic solid papillary carcinoma with invasion. The tumor was a clear-cell type with extracellular mucin. Two months after the initial biopsy, a screening ultrasonographic examination of the liver showed multiple hyperechoic masses. Abdominal contrast-enhanced CT scan and magnetic resonance imaging (MRI) showed multiple hypervascular masses compatible with metastatic tumors. No suspicious lesions were detected on examinations for malignancy in other organs. Distant metastases in cases of IPC with invasion are very rare. The potential of distant metastasis in IPC with invasion and the difficulty of evaluating invasive foci should be recognized. Careful evaluation of distant metastases is recommended.

HER2 protein overexpression in estrogen receptor-positive ductal carcinoma in situ of the breast: frequency and implications for tamoxifen therapy

Recent clinical data have suggested that the efficacy of tamoxifen in reducing the risk of local recurrence following lumpectomy and radiation therapy in patients with ductal carcinoma in situ (DCIS) is limited to patients with estrogen receptor (ER)-positive lesions. However, it is currently not known if HER2 protein overexpression might be associated with reduced tamoxifen benefit in patients with ER-positive DCIS, as has been suggested in patients with ER-positive invasive breast cancer and in preclinical models. Moreover, the frequency of HER2 overexpression in ER-positive ductal carcinoma in situ has not been previously evaluated in detail. To address this issue, we studied ER expression and HER2 overexpression in 148 cases of DCIS using a sensitive double immunostaining technique and assessed the frequency of ER expression and HER2 overexpression in relation to each other and in relation to DCIS grade. Overall, ER expression was seen in 114 cases (77%) and HER2 protein overexpression was seen in 42 cases (28%). Of 114 ER-positive ductal carcinoma in situ, 14 (12%) showed concurrent HER2 protein overexpression, and all 14 of these DCIS lesions were of high nuclear grade. In addition, in all 14 ER-positive DCIS cases that showed HER2 overexpression, double immunostaining demonstrated that ER and HER2 protein were coexpressed by the same neoplastic cells. We conclude that a subset of ER-positive DCIS show concomitant overexpression of HER2 protein. Whether or not HER2 overexpression is associated with a diminished response to tamoxifen in patients with ER-positive DCIS will require investigation in clinical outcome studies.

High frequency of G/C transversion on p53 gene alterations in breast cancers from Taiwan

p53 gene mutation is a very frequent event in many human cancers and is associated with a poor clinical outcome in breast cancer patients. Analysis of p53 gene mutations can also provide clues to the etiology of tumor formation. The present study was conducted to investigate the p53 mutations in patients with breast cancer from Taiwan. Tumor samples from 119 patients undergoing mastectomy for breast cancer were evaluated. The mutational status of the p53 gene (exons 5-8) was screened by polymerase chain reaction-single strand conformation polymorphism analysis followed by direct sequencing. Of all 119 cases of breast carcinoma, 26 mutations of the p53 gene were found in 22 cases (18.5%). Among these mutations, 78% (20/26) were point mutations with the majority of those being missense mutations (75%, 15 of 20 mutations) and the other 22% (6/26) were frameshift mutations. No significant correlation between p53 mutations and clinicopathological features was found, including HER2 status. Moreover, our results disclosed distinct mutation spectra in excess transversions to transitions (15/21, 71.4% vs. 6/21, 28.6%) with GC to CG dominant (6/15, 40%). Mutation hot spots we identified at codons 167, 185, 186, 210, 265 and 295 have rarely been documented in the literature. These findings showed that p53 gene mutation might contribute to the pathogenesis of breast carcinoma. Furthermore, the different mutation spectrum with high transversions in G:C to C:G may imply that the exogenous mutagens outweigh the endogenous processes in breast cancer in patients in Taiwan.

Histological classification of invasive ductal carcinoma and the biological parameters in breast cancer

BACKGROUND

The histological classification of invasive ductal carcinoma proposed by the Japanese Breast Cancer Society is based on the appearance of breast cancer invasion. However, few studies have been done to clarify the relationship between the histological classification and other parameters that represent the biological characteristics of individual breast cancer cells.

MATERIALS AND METHODS

We analyzed 1,025 invasive ductal carcinomas, consisting of 424 papillotubular, 330 solid-tubular and 271 scirrhous cases, with regard to the status of estrogen receptor (ER), progesterone receptor (PgR), DNA ploidy, epidermal growth factor receptor (EGFR) and p53 protein.

RESULTS

Absence of ER and PgR, aneuploidy, EGFR positivity and p53 protein positivity were all observed significantly more frequently in solid-tubular tumors than in the other two types. In addition, the number of abnormal features with regard to these 5 biological parameters was also significantly higher in solid-tubular tumors than in the other two types.

CONCLUSION

Abnormalities in the biological parameters listed above were frequently found in the solid-tubular type of invasive ductal carcinoma.

Molecular evolutionary patterns in breast cancer

Geno-phenotypic patterns of pre-invasive and invasive lobular breast cancers and infiltrating ductal carcinomas of low, intermediate, and high grade are reviewed. One of the main differences between lobular breast cancers and ductal carcinomas is the presence of inactivating E-cadherin gene mutations in lobular breast cancers. In many other respects, lobular breast cancers and low-grade ductal carcinomas exhibit similar geno-phenotypic profiles. The development of p53 dysfunction may be a hallmark of infiltrating ductal cancers of intermediate and high grade. Sequential Her-2/neu and ras abnormalities define a subset of aggressive high-grade tumors, and the development of Rb dysfunction may define a separate subset of aggressive ductal cancers. Based on these observations, a branching molecular evolutionary model for the development and progression of breast cancer is proposed.

Histological and immunohistochemical analysis of apocrine breast carcinoma

BACKGROUND

There are few data regarding the biological characteristics of apocrine breast carcinoma in the literature due to its rarity and controversy over its definition. We analyzed the histopathological characteristics and tumor biology of apocrine breast carcinomas with regard to histological grade, p53, HER2, bcl-2, MIB-1 and hormone receptor status.

PATIENTS AND METHODS

A consecutive series of 24 female apocrine breast carcinoma patients were the primary source of these retrospective data. Background factors including histological grade, nodal status and lymphatic invasion by tumor cells were analyzed. Immunohistochemical staining for p53, HER2, MIB-1, bcl-2, estrogen receptor (ER) and progesterone receptor (PR) was carried out on formalin-fixed, paraffin embedded specimens.

RESULTS

Older age and postmenopausal status were observed more frequently in patients with apocrine breast carcinoma than those with invasive ductal carcinoma. Apocrine breast carcinoma also showed relatively lower histological grade than invasive ductal carcinoma. Nuclear accumulation of p53, HER2 overexpression, bcl-2 and MIB-1 index were observed in 29% (7/24), 33%(8/24), 25%(6/24) and 29% (7/24) of cases, respectively. Positivity for ER and PR was present in 17% (4/24) and 17% (4/24) of cases, respectively.

CONCLUSIONS

Apocrine breast carcinoma tended to show low MIB-1 index, low bcl-2 expression and low positive rate of hormone receptors. There was no correlation between the three types of apocrine carcinoma and the positivity rate of p53, HER2, bcl-2, MIB-1 and hormone receptor status.

Histological grade, p53, HER2 and hormone receptor status of synchronous bilateral breast carcinoma

BACKGROUND AND OBJECTIVES

Histological grade and tumor biology remain important predictors of the clinical behavior of breast carcinomas. We analyzed the clinicopathological characteristics and tumor biology with regard to histological grade (HG), p53, HER2 and hormone receptor status to address this question.

PATIENTS AND METHODS

A consecutive series of 74 female synchronous bilateral breast carcinoma patients treated at the National Cancer Center Hospital were the primary source of these retrospective data. Clinicopathological background factors, histological grade and immunohistochemical staining for p53, HER2 and hormone receptor status, were analyzed.

RESULTS

Of 148 synchronous bilateral tumors, 102 were invasive ductal carcinoma (IDC). The others included 24 pure or predominant ductal carcinoma in situ (DCIS), 5 spindle cell carcinomas, 16 invasive lobular carcinomas and 1 squamous cell carcinoma. 128 cases (128/148: 89%) were HG 1 (72/148: 49%) or HG 2 (56/148: 38%). The positivity rates for p53, HER2, estrogen receptor (ER) and progesterone receptor (PR) were 9%(14/148), 18%(26/148), 64%(95/148) and 64%(95/148), respectively.

CONCLUSION

Our findings indicate that synchronous bilateral breast carcinomas showed a higher frequency of invasive lobular carcinoma, lower HG and higher rate of hormone receptor positivity than unilateral breast carcinomas.

Prognostic and predictive factors in the adjuvant treatment of breast cancer

The selection of systemic adjuvant therapy should be based on the appropriate prognostic and predictive factors. The established prognostic factors currently used in cases of primary breast cancer include axillary lymph node involvement, histologic subtype, tumor size, nuclear or histologic grade, estrogen (ER) and progesterone receptor (PR) status and proliferative index. Adjuvant chemotherapy has had an impact on the management of node-positive breast cancer, while the St. Gallen recommendations were established for postoperative adjuvant therapy for node-negative breast cancer. However, there is some contention regarding the histological (or nuclear) grading systems among different pathologists. With regard to biological measurements, the most useful prognostic/predictive factors are hormone receptor status and HER-2 overexpression. ER and PR status can be used to establish the necessity of hormone therapy in the adjuvant setting. If the anti-HER-2 antibody and/or antiangiogenic agents are introduced into the adjuvant setting in the near future, determination of these factors is also recommended.

Low frequency of p53 gene mutations in breast cancers of Japanese-American women

Differences in frequencies and patterns of somatic p53 gene mutations among racially and geographically diverse populations presumably reflect exposure to different mutagens or different responses to certain mutagens. On emigration to the United States, Japanese women experience, over several generations, a four- to fivefold increase in the incidence of breast cancer. To determine whether this increased incidence is associated with a change in the frequency and/or type of p53 mutation in their tumors, we examined paraffin-embedded samples of primary breast cancers from Japanese-American women in Los Angeles County, CA. Mutations in exons 5-9 and adjacent intronic regions of the p53 gene were identified and confirmed by direct sequencing. Seven mutations, including 5 missense, were detected in 44 primary breast carcinomas, a frequency of 16%. There were six transitions and one transversion. As expected, overexpression of p53 protein, detected by immunohistochemistry, occurred in tumors with missense mutations; tumors with nonsense or splice junction mutations had no detectable p53 protein. The frequency of p53 gene mutations showed no increase over that previously found in breast cancers of native Japanese women. The increased incidence of breast cancer in Japanese-American women is likely to be multifactorial in nature and warrants further studies.

p53 missense mutations in microdissected high-grade ductal carcinoma in situ of the breast

BACKGROUND

To understand the role of sporadic mutations in the tumor suppressor gene p53 (also known as TP53) in the pathogenesis of breast cancer, it is important to identify at which histologic stage such mutations first occur. We previously showed that a p53 mutation present in invasive breast cancer was found in all surrounding areas of ductal carcinoma in situ (DCIS) but not in areas of hyperplasia or normal breast epithelium. In the present investigation, we studied patients with DCIS, but without invasive breast cancer, to determine the spectrum of DCIS types that can harbor a p53 mutation.

METHODS

Formalin-fixed, paraffin-embedded tissues from 94 patients with DCIS were evaluated histologically for the predominant cellular architectural pattern, degree of necrosis, and nuclear grade. Each specimen was also assigned an overall histologic grade (with the use of the Van Nuys Prognostic Index pathologic classification). Tissue specimens were stained immunohistochemically with an anti-p53 antibody. Positively stained tissue areas were analyzed for the presence of p53 mutations by single-strand conformation polymorphism and direct sequencing. All statistical tests were two-sided.

RESULTS

DCIS from 10 of 94 patients were found to contain p53 missense mutations. All 10 were of a solid or a comedo histologic pattern and contained cells of nuclear grade 2 or 3 (i.e., more abnormal nuclei). The frequency of p53 missense mutations was statistically significantly different among the three overall histologic grade categories (zero [0%] of 49 with low-grade DCIS, one [4.35%] of 23 with intermediate-grade DCIS, and nine [40.9%] of 22 with high-grade DCIS; df = 2 and P<.0001).

CONCLUSION

The DCIS types in patients in this series are representative of clinically detected DCIS. Our finding that p53 mutations can occur before the development of invasive breast cancer, particularly in DCIS of high histologic grade, has potentially important implications for prevention and treatment.

Differences in estrogen receptor status, HER2, and p53 comparing metachronous bilateral breast carcinoma

BACKGROUND AND OBJECTIVES

We analyzed the clinicopathologic characteristics and tumor biology of metachronous bilateral breast carcinoma with regard to p53, HER2 and hormone receptor status.

METHODS

A consecutive series of 54 female metachronous bilateral breast carcinoma patients treated at the National Cancer Center Hospital between 1980 and 1997 were the primary source of these retrospective data. Clinicopathologic background factors were analyzed, and immunohistochemical staining for p53, HER2, and hormone receptor status was carried out on paraffin-embedded specimens.

RESULTS

There were no significant differences in clinical stage, p53 and HER2 expression levels between the first and second primary tumors. The positive rates for ER and PR were 48% (25 of 52) and 46% (25 of 54) for the first tumors, but only 19% (10 of 52) and 32% (17 of 54) for the second tumors (P = 0.004 for ER, P = 0.16 for PR), showing a significant loss of ER.

CONCLUSIONS

Our findings indicate that p53 and HER2 expression levels in the second tumors might be the same as those of the first tumors in metachronous bilateral breast carcinoma; however, loss of ER was more frequently observed in the second primary tumors than in the first tumors.

Biological features of premalignant disease in the human breast

Most human invasive breast cancers (IBCs) arise from preexisting benign lesions. There are many types of benign lesions in the human breast and only a few appear to have significant premalignant potential (atypical hyperplasias and in situ carcinomas). These lesions are relatively common and only a small proportion progress to IBC. They are currently defined by their histological features and their prognosis is imprecisely estimated from indirect evidence based on epidemiological studies. Although lesions within specific categories look alike, they must possess morphologically silent biological differences motivating some to remain stable and others to progress. Understanding the biological changes responsible for the development and progression of premalignant disease is a very active area of medical research. Progress in this area may provide new opportunities for breast cancer prevention by providing strategies to treat premalignant lesions before they develop or become cancerous. A large number of biological features have been evaluated in this setting during the past decade. This review discusses a few features that appear to be particularly important and have been studied in a relatively comprehensive manner.

Ductal carcinoma in situ. Implications for screening mammography

Ductal carcinoma in situ (DCIS) now represents 20% of all newly diagnosed breast cancers because of increased detection by screening mammography. Twenty year relative survival rates are 97%. Postsurgical and histological studies and recent molecular biological studies indicate that most cases of DCIS will progress to invasive carcinoma if not detected by mammography. Screening mammography studies support the need for annual versus less frequent screenings to detect DCIS before further progression.

c-erbB-2 protein overexpression and p53 immunoreaction in primary and recurrent breast cancer tissues

BACKGROUND AND OBJECTIVES

We investigated whether expression levels of c-erbB-2 and p53 proteins in breast cancer tissues differ in primary and metastatic lesions.

METHODS

Immunohistochemical staining or sandwich enzyme immunoassay was used to determine expression levels of c-erbB-2 and p53 proteins in 42 breast cancer samples from 21 patients. Estrogen (ER) and progesterone receptors (PgR) were also measured by enzyme immunoassay in each case. All patients had undergone radical surgery for primary tumors and surgical resection of asynchronous metastatic lesions. Thirteen patients (62%) were premenopausal and 14 (67%) received postoperative adjuvant therapies. Median disease-free survival time was 26 months (range, 5-104). The resected metastatic lesions included 1 in the liver, 3 in the lung, and 3 in the supraclavicular lymph nodes. The remaining 14 were local skin lesions.

RESULTS

There was no difference in the positivity rate of c-erbB-2 (38%: 8/21) and p53 (39%: 7/18) expression between the primary tumors and the recurrent lesions. In addition, no discordant c-erbB-2 or p53 expression was observed between the primary tumors and their respective metastatic lesions. Positivity rates for ER and PgR were 50% (10/20) and 60% (12/20) for the primary tumors, but only 25% (5/20) and 30% (6/20) for the recurrent lesions, respectively (P = 0. 19 for ER and P = 0.11 for PgR).

CONCLUSIONS

c-erbB-2 and p53 expression levels in breast cancer cells were almost unchanged as the disease progressed and/or in response to adjuvant therapies, regardless of the hormone receptor status.

p53 mutations and expression in breast carcinoma in situ

The p53 tumor suppressor gene is altered in approximately half of human cancers. Although p53 mutations are common in invasive breast carcinoma, few have been identified in breast carcinoma in situ (intraductal breast carcinomas). Most studies of p53 in breast carcinoma in situ are immunohistochemical studies of p53 staining in paraffin-embedded tissue sections. Few studies have isolated the tumor cells and subjected them to DNA sequence analysis. The current study was undertaken to characterize p53 in a cohort of breast carcinoma in situ cases, both with and without invasive disease. Fifty-eight frozen breast biopsy samples were used for these investigations. Twenty-seven cases had only ductal carcinoma in situ (CIS) and 31 cases had evidence of both invasive and in situ carcinoma. DNA sequence alterations in exons 2 through 11 of p53 were screened by the single-strand conformational polymorphism technique. Exons with altered mobility were sequenced. Among breast CIS cases without invasive disease, 22% had p53 mutations and 7% had DNA sequence alterations of unknown significance. Analysis of breast CIS with concurrent invasive disease demonstrated p53 mutations in 19% of cases and one (3%) DNA alteration of unknown significance. Each carcinoma having a p53 mutation in the breast CIS component had the identical mutation in the invasive component of the same tumor indicating a clonal relationship between the two tumor components. p53 protein overexpression was identified in 22% of pure intraductal breast carcinomas and in 35% of breast CIS with invasive disease. Comparison of immunostaining and DNA sequence alterations showed a significant association between overexpression and mutations (P = 0. 0037) in cases of CIS without invasion, and similarly between overexpression and mutations in cases of CIS with invasion (P = 0. 007). p53 mutations and p53 overexpression were relatively common in intraductal breast carcinomas but were not observed in adjacent normal breast lobules or ducts in 9 cases available for DNA analysis. The frequency of p53 alterations when comparing breast CIS with and without an invasive component indicated that p53 mutations usually occur before invasion during the progression of breast cancer, as is observed for a number of other adult solid tumors.

Prognosis of a series of 763 consecutive node-negative invasive breast cancer patients without adjuvant therapy: analysis of clinicopathological prognostic factor

BACKGROUND AND OBJECTIVES

The objectives of this study were to confirm the favorable outcome of Japanese invasive breast cancer patients without lymph node metastasis, after treatment with surgery alone, and to evaluate clinicopathological prognostic factors in this population.

METHODS

The subjects were 763 consecutive node-negative invasive breast cancer patients who underwent surgery without adjuvant therapies between 1988 and 1993 at our hospital. Disease-free survival (DFS) and overall survival (OS) rates were analyzed by clinicopathological factors.

RESULTS

The median age of the patients at surgery was 52 years and the median follow-up period of patients was 74 months. At 5 years, the respective DFS and OS rates of all patients were 90.8% and 93.9%. Patients with a pathological tumor size of invasive component of more than 2 cm (319 patients) had a significantly lower DFS than those with tumors measuring 2 cm or less (361 patients) (P = 0.045). Patients with positive hormone receptor status (280 patients) (estrogen and/or progesterone receptor positive) tended to have a better OS than those negative for both hormone receptors (92 patients) (P = 0.078). Meanwhile, patients with tumors of histological grade 3 (328 patients) had a much poorer prognosis than those with tumors of histological grade 1 or 2 (413 patients) (P = 0.008 for OS and P = 0.042 for DFS). The respective 5-year DFS and OS rates of patients with histological grade 3 tumors larger than 2 cm in pathological tumor size of invasive component (195 patients) were 85.5% and 87.6%, indicating that these node-negative patients form a high risk group.

CONCLUSIONS

Japanese invasive breast cancer patients without lymph node metastasis tended to show a survival advantage compared with their Caucasian counterparts. Histological grade was the most useful prognostic factor in this population.

Comparative genomic hybridization of ductal carcinoma in situ of the breast-evidence of multiple genetic pathways

There is strong evidence that ductal carcinoma in situ (DCIS) represents a precursor lesion of invasive breast cancer. In order to analyse specific chromosomal alterations of DCIS, 38 paraffin-embedded specimens of DCIS and six associated invasive carcinomas were examined by means of comparative genomic hybridization (CGH). Losses of 16q material were seen almost exclusively in well- and intermediately-differentiated DCIS. These two subgroups differed in the average number of genetic imbalances, 2.5 and 5.5 respectively. Additionally, a higher frequency of gains of 1q and losses of 11q material was seen in intermediately-differentiated in contrast to well-differentiated DCIS. Poorly-differentiated DCIS displayed a higher frequency of amplifications (17q12, 11q13) and a higher average rate of genetic imbalances (7.1). Analysis of adjacent invasive breast carcinoma revealed a genetic pattern almost identical to the one seen in the DCIS counterpart. These data characterize DCIS as a genetically far-advanced, heterogeneous lesion and as a direct precursor of invasive breast cancer.

Prognostic significance of mutations in the p53 gene, particularly in the zinc-binding domains, in lymph node- and steroid receptor positive breast cancer patients. Austrian Breast Cancer Study Group

The aim of our study was to evaluate if p53 mutations, especially those in the L2/L3 domains of the p53 gene, add prognostic information for node-positive and steroid receptor positive breast cancer patients. Two hundred and five tumour samples from a randomised clinical trial of 596 lymph node- and steroid receptor positive breast cancer patients were included. All patients had been randomly allocated to receive 20 mg of adjuvant tamoxifen (TAM) daily for 2 years or TAM plus one cycle of low-dose, short-term chemotherapy. For detection of p53 mutations we used in vitro amplification by polymerase chain reaction and consecutively performed temperature gradient gel electrophoresis (PCR-TGGE) and direct sequencing. We found p53 mutations in 42/205 (20%) cases: 16/42 (38%) p53 mutations occurred within the L2/L3 domains of the p53 gene, and 26/42 (62%) outside the L2/L3 domains. p53 mutation served as a statistically significant parameter in predicting disease-free survival in univariate (P = 0.02) and multivariate (P = 0.009) analysis. For overall survival, no significant differences were observed. Patients with tumours that had p53 mutations within the L2/L3 domains of the gene showed no significant difference to those with mutations outside the L2/L3 domains for disease-free survival. For overall survival, mutations in the L2/L3 domains showed a marginally significant difference (P = 0.05) in multivariate analysis, but not in univariate analysis (P = 0.13). We conclude that mutation in the L2/L3 domains of the p53 gene is not an independent prognostic indicator of disease outcome for patients suffering from breast cancer with lymph node metastases and positive steroid receptors.

Genomic organization of the canine p53 gene and its mutational status in canine mammary neoplasia

To determine whether canine malignancies share common genetic lesions with their human counterparts, and are thus potentially interesting model systems in which to pose questions regarding tumor etiology and progression, we have elucidated the entire exon/intron structure of the canine p53 gene. A search for p53 gene abnormalities in mammary tumor tissue was undertaken utilizing single strand conformation polymorphism analysis. Mutations were detected in exons 4, 5, 6, and 7 of the p53 gene and consisted of nonsense, splicing, and frameshift mutations. None of 11 benign tumors and 6 of 40 primary carcinomas (15%) were found to harbor subtle p53 mutations. In 14 carcinomas examined the results in primary tumors and metastases were the same. These findings implicate involvement of this gene in the genesis of some malignant canine tumors, in a fashion similar to their human counterparts.

A prospective study of the significance of gene and chromosome alterations as prognostic indicators of breast cancer patients with lymph node metastases

In 150 surgically resected primary breast carcinomas that had axillary lymph-node metastases, we examined the incidence of loss of heterozygosity on chromosomes 16p, 16q, 17p, 17q, and 18q, point mutation of the p53 tumor-suppressor gene, nuclear immunoreaction of p53 protein, and amplifications of the c-erbB-2 and int-2 oncogenes by Southern blotting, single-strand conformation polymorphism analysis, and immunohistochemistry. We analyzed the association of these factors and conventional prognostic parameters with outcome of the patients, using Cox's univariate and multivariate analyses. The univariate analysis revealed that nuclear p53 immunoreaction, p53 mutation, and c-erbB-2 amplification as well as the number of metastatic lymph nodes, histological grade, and hormone-receptor statuses were significant prognostic indicators for both recurrence and cancer death. p53 immunoreaction was correlated more strongly with a poor prognosis than p53 mutations. The combination of p53 and c-erbB-2 effectively identified the high-risk patient group, and even among Grade 3 cases the subgroup with these alterations tended to have poorer clinical outcomes. The multivariate analysis including p53, c-erbB-2, and conventional factors. Lymph node status, grade, and p53 had independent impacts on the survival of patients. Under identical adjuvant systemic therapies, prognoses differed between the patient groups with and without alterations of p53 or c-erbB-2. Appropriate combinations of conventional factors with nuclear p53 immunoreaction and c-erbB-2 amplification would help to identify highly aggressive node-positive breast carcinomas and would aid stratification of patient groups in randomized clinical trials of adjuvant systemic therapies.

Allelic imbalance at chromosome 17p13.3 (YNZ22) in breast cancer is independent of p53 mutation or p53 overexpression and is associated with poor prognosis at medium-term follow-up

Molecular and immunohistochemical studies of genetic events on chromosome 17p were prospectively compared with conventional clinical and pathological parameters and disease behaviour at a minimum of 72 months follow-up. In a series of 91 patients with primary operable breast cancer, 37 out of 91 (41%) patients had disease relapse and 23 out of 91 (25%) had died during the follow-up period. Allelic imbalance at the YNZ22 locus (17p13.3), demonstrated in 33 out of 63 (52%) informative patients, was significantly associated with disease recurrence (P < 0.01, 2 d.f. Cox analysis) and showed a trend towards impaired survival (P = 0.08, 2 d.f. Cox analysis) after a mean follow-up of 84 months for survivors. By contrast, p53 mutation (in 10 out of 60, 17% of cancers), p53 allelic imbalance (in 23 out of 56, 41% informative patients), p53 mRNA expression (in 47 out of 87, 54% patients), p53 mRNA overexpression (in 24 out of 87, 28%) or p53 protein expression (detected in 25/76, 32%) were not associated with disease behaviour. There was no significant association between allelic imbalance at YNZ22 and any abnormality of p53 DNA, RNA or protein. Allelic imbalance at 17p13.3 (YNZ22) serves as a marker of poor prognosis in breast cancer. As yet unidentified genes on 17p13.3, distinct from and telomeric to p53, are therefore likely to be of clinical importance in breast cancer.

Microinvasive breast carcinoma with extensive involvement of level III axillary lymph nodes: a case report

A 44-year-old woman presented with a right huge axillary mass. Both mammography and ultrasonography revealed a primary cancer of 2.8 cm maximum diameter in the right breast and metastases in the axillary lymph nodes, both being confirmed by aspiration cytology as ductal carcinoma. Right standard radical mastectomy with level III axillary lymph node dissection was carried out. Pathologically, the tumor was diagnosed as ductal carcinoma in situ with microinvasion (DCISM), histologic grade 3. The area of stromal invasion measured 1 mm at its widest point. Sixteen of the 17 resected axillary lymph nodes contained metastases, including six level III lymph nodes. Immunohistochemical studies of the tumor revealed overexpression of p53 protein, but not that of c-erbB-2 protein. The frequency of lymph node metastases from DCISM is reported to be very low. Therefore, the present case with extensive involvement of level III lymph nodes was unusual.

Prognostic significance of accumulation of gene and chromosome alterations and histological grade in node-negative breast carcinoma

The histological grade of atypia is a known prognostic indicator for breast cancer patients and correlates with many gene and chromosome alterations. To investigate the independent prognostic significance of gene and chromosome alterations in axillary node-negative (n0) breast cancers of the invasive ductal and invasive lobular types, the prevalence of eight gene and chromosome alterations and their association with histological grade and recurrence was studied in 129 consecutive patients who had undergone resection over an average follow-up period of 43.4 months. Loss of heterozygosity on 16q, 17p, 16p, 17q and 18q, p53 gene mutation and c-erbB-2 and int-2 gene amplifications were detected in 55%, 37%, 25%, 24%, 22%, 23%, 15% and 11% respectively. Individual alterations in 17p, 17q, 18q, c-erbB-2 and p53 were detected most frequently and gene and chromosome alterations tended to be accumulated in Grade 3 n0 invasive ductal/lobular carcinomas. Histological grade, 18q, int-2 and the number of these gene and chromosome alterations were significant prognostic indicators on Cox's univariate proportional hazard model, and 18q and int-2 were still significant after adjustment for histological grade. Results suggested that examination of the presence of certain gene and chromosome alterations, as well as histological grade, were effective in identifying n0 breast cancer patients at high risk of early recurrence.

Original p53 status predicts for pathological response in locally advanced breast cancer patients treated preoperatively with continuous infusion 5-fluorouracil and radiation therapy

PURPOSE/OBJECTIVE

1) To test feasibility of preoperative continuous infusion (c.i.) 5-Fluorouracil (5-FU) and radiation (RT) in locally advanced breast cancer. 2) To study clinical and pathological response rates of 5-FU and radiation. 3) To attempt preliminary correlations between biological probes and pathological response.

METHODS AND MATERIALS

Previously untreated, locally advanced breast cancer patients were eligible: only patients who presented with T3/T4 tumors that could not be resected with primary wound closure were eligible, while inflammatory breast cancer patients were excluded. The protocol consisted of preoperative c.i. infusion 5-FU, 200 mg/m2/day with radiotherapy, 50 Gy at 2 Gy fractions to the breast and regional nodes. At mastectomy, pathological findings were classified based on persistence of invasive cancer: pathological complete response (pCR) = no residual invasive cells in the breast and axillary contents; pathological partial response (pPR) = presence of microscopic foci of invasive cells in either the breast or nodal specimens; no pathological response (pNR) = pathological persistence of tumor. For each patient pretreatment breast cancer biopsies were analyzed by immunohistochemistry for nuclear grade, ER/PR hormonal receptors, her2/neu and p53 overexpression.

RESULTS

Thirty-five women have completed the protocol and are available for analysis. 5-FU was interrupted during radiation in 10 of 35 patients because of oral mucositis in 8 patients, cellulitis in 1, and patient choice in another. Objective clinical response rate before mastectomy was 71% (25 of 35 patients): 4 CR, 21 PR. However, in all 35 patients tumor response was sufficient to make them resectable with primary wound closure. Accordingly, all patients underwent modified radical mastectomy: primary wound closure was achieved in all patients. At mastectomy there were 7 pCR (20%), 5 pPR (14%) and the remaining 23 patients (66%) had pathological persistence of cancer (pNR). Variables analyzed as potential predictors for pathological response (pPR and pCR) were: initial TNM clinical stage, clinical response, nuclear grade, hormonal receptor status, p53 overexpression, and Her2/neu overexpression in the pretreatment tumor biopsy. Only initial p53 status (lack of overexpression at immunohistochemistry) significantly correlated with achievement of a pathological response to this regimen (p = 0.010).

CONCLUSION

The combination of c.i. 5-FU and radiation was well tolerated and generated objective clinical responses in 71% of the patients. With the limitation of the small sample size, the complete pathological response achieved (20%) compares favorably with that reported in other series of neoadjuvant therapy for similar stage breast cancer. These preliminary data suggest that initial p53 status predicts for pathological response (pPR and pCR) to the combination of c.i. 5-FU and radiotherapy in locally advanced breast cancer.

An intronic deletion in TP53 gene causes exon 6 skipping in breast cancer

Six hundred and thirty primary breast cancer were screened for abnormalities in exons 5, 6, 7 and 8 of the TP53 tumour suppressor gene. Analysis of the structure of the TP53 gene exons was performed with the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method and with direct sequencing of amplified DNA. In a breast tumour case from a postmenopausal patient, we found a deletion of 36 bp in intron 5 and no immunohistochemical staining for p53. We amplified and sequenced the cDNA region between exons 4 and 7 and showed that the deletion causes the skipping of exon 6. The resulting mRNA sequence had a frameshift that yields an inactive protein with a truncated C terminus. These results show the first example of intronic deletion causing exon skipping at the TP53 gene level.

p53 tumor suppressor protein and tissue proliferative fraction in infiltrating duct carcinoma

BACKGROUND AND OBJECTIVES

Breast cancer continues to frustrate oncologists worldwide. In India, it is the second most common neoplasm among women and is increasing in incidence. Several molecular markers have been associated with a poor prognosis in patients with breast cancer, and the presence of these markers is often thought to provide information on the biological behavior of the malignant breast tumor. Much attention has recently been focused on the tumor suppressor gene p53. Mutation or alteration in this gene leads to the loss of negative growth regulation and hence to rapid cell proliferation. The present study was designed to evaluate the connection between expression of the p53 protein and its relation to the tissue proliferative compartment as measured by expression of the proliferating cell nuclear antigen (PCNA).

METHODS

Expression of p53 and PCNA were detected by immunocytochemistry in paraffin-embedded sections of infiltrating duct carcinoma and control breast tissue (normal tissue and adenoma).

RESULTS

A significant correlation was observed between expression of p53 and PCNA. A significant correlation was also observed between expression of p53 and grade of tumor and stage of disease.

CONCLUSIONS

Our results support the hypothesis that accumulation of p53 is associated with a high tumor proliferation rate an association that might be expected in view of the role of wild p53 as a negative regulator of cell proliferation.

Detection of p53 gene mutations in fine-needle aspiration biopsied breast cancer specimens: correlations with nuclear p53 accumulations and tumor DNA aneuploidy patterns

Using the polymerase chain reaction and a single strand conformation polymorphism (PCR-SSCP) analysis, p53 gene mutations have been examined preoperatively in aspirated biopsy specimens from 22 breast cancers. In eight (36%) of the studied cases, abnormal bands indicating mutations were detected and were more frequently present in common invasive breast carcinomas. Eight of the breast cancer cases were found to be positive for mutations: direct DNA sequencing confirmed eight mutations and revealed G to A and A to G nucleotide changes in five (63%) and two (25%) cases, respectively. The mutations that were localized at the CpG site of the gene were seen in three cases. Additionally, an immunohistochemical investigation of the presence of the p53 protein and a DNA flow-cytometrical analysis of the 22 resected breast cancers were also performed. Nuclear p53 protein accumulations and a DNA aneuploidy pattern were detected in 11 (50%) cases and in 16 (73%) cases, respectively, and both significantly correlated with p53 gene mutations (P < 0.01 and P < 0.001, respectively; Fisher's exact test). In contrast, in five cases of a breast cancer with a lower histologic grade, no p53 gene mutations, nuclear p53 protein accumulations, or DNA aneuploidy patterns were detected. These results thus suggest that p53 gene mutations, nuclear accumulations of the p53 protein, and a DNA aneuploidy pattern are events that occur with close relationship in the progression of a breast cancer, and that p53 abnormalities appear to correlate with a high grade of the malignancy. Therefore, the detection of p53 gene mutations in aspirated biopsy specimens of breast cancers may be helpful for an accurate and rapid cytological diagnosis, which reflects the prognosis.

p53 protein expression in ductal carcinoma in situ (DCIS) of the breast

Abnormalities in p53 gene expression have been implicated in many inherited and sporadic forms of malignancies in humans. Immunohistochemical staining using monoclonal antibody D0-7 for the p53 protein expression was performed in 81 cases of pure DCIS, 14 benign breast lesions and 2 cases with normal breast tissue. Expression of p53 protein was detected in 15 (18.5%) cases of pure DCIS. Thirteen (25%) of the 52 comedo type DCIS showed p53 protein expression compared with 2 (6.9%) of the 29 non-comedo types (P < 0.02). p53 protein expression was also associated with high nuclear grade (P < 0.001) and high mitotic index (P < 0.05). The pattern of p53 protein staining was diffuse in one comedo type DCIS, regional in 6 comedo types, and focal in the remaining 8 cases (6 comedo type and 2 micropapillary type DCIS). The patient with comedo type DCIS showing diffuse staining has a family history of breast cancer in the first and second degree relatives (sister and maternal aunt). Clinical follow-up data was available in 52 cases. Follow-up period ranged from 9 to 55 months. Three patients, who were primarily treated by local excision, have had a documented local recurrence in the form of residual tumor within a short interval of 5 to 11 months. In all these three patients both the original and the recurrent tumors are negative for p53 protein expression. The difference in the local recurrence rate between p53 positive (0/15) and p53 negative (3/37) cased does not reach statistical significance (p > 0.05). We interpret that the local tumor recurrence in these three cases within a short period after primary excision is due to the presence of residual tumor at the excision site and is independent of the p53 gene alteration. It is concluded that p53 protein expression in DCIS is associated with comedo subtype, high nuclear grade, and high mitotic index, and is a promising new parameter to evaluate the cellular biology and prognosis of DCIS.

p53 gene mutations and expression of p53 and mdm2 proteins in invasive breast carcinoma. A comparative analysis with clinico-pathological factors

The aim of the study was to analyze p53 gene mutations and the expression of p53 and mdm2 proteins in 31 randomly selected invasive breast carcinomas. The results were then correlated with tumor grade, stage, estrogen receptor status, nodal status, and DNA ploidy. The expression of the proteins p53 and mdm2 was determined immunohistochemically using formalin-fixed, paraffin-embedded material. Screening for p53 mutation involved analysis of the highly conserved regions of the p53 gene (exons 5-9) by the polymerase chain reaction/ single-strand conformation polymorphism (PCR-SSCP) technique. PCR products with band shifts were directly sequenced. Immunohistochemical staining of p53 was positive in 9 cases (29.0%), only 2 of which showed a p53 gene mutation. These were identified as a C-->G transversion at the second position of codon 278 in exon 8 and an A-->G transition at the second position of codon 205 in exon 6. A third case with a mutation was observed (C-->T transition, position 1 of codon 250 in exon 7) that did not show p53 immunohistochemically. Of the 9 p53-positive tumors, 2 were moderately differentiated (grade II). The remaining tumors were poorly differentiated (7/9). By contrast, p53-negative carcinomas were well differentiated (grade I) in most cases (P = 0.02). DNA cytometry in 8 of the 9 p53-positive carcinomas revealed an aneuploid stem line. The majority of the p53-negative tumors were diploid (P = 0.01). Mdm2 oncoprotein was detected in 10 tumors (32.2%), 4 of which were p53-positive, including the 3 with mutations. The grading of the mdm2-positive tumors was moderate or poor, G1 carcinomas were always noted to be mdm2-negative (P = 0.04). Overexpression of p53 protein is a complex mechanism and does not merely indicate the detection of mutations in the p53 gene. This study has shown that p53 expression correlates with tumor grade and DNA ploidy. Mdm2 expression was also associated with the tumor grade. Immunohistological demonstration of the p53 protein alone is insufficient as a basis for comment on the functional state of the p53 gene and gene product. The interrelation between recognition of the p53 protein and gene mutation needs more careful assessment to define their roles in the control of neoplasia.

The molecular epidemiology of p53 gene mutations in human breast cancer

The P53 tumor-suppressor gene is an advantageous tool for analyzing the molecular epidemiology of cancer. We describe the utility of the P53 gene as a 'mutagen test' and a prognostic indicator in breast cancer. Aspects of study design and methodology are discussed. Two major conclusions emerge: (1) there is an extraordinary diversity of mutational patterns among cohorts, hinting that the unique biology of mammary cells results in exposure to high doses of a diversity of ingested lipophilic mutagens; and (2) mutations in the P53 gene predict poor outcome in breast cancer.

Recent Progress in Breast Conserving Therapy: From Experiences in Japan

Breast conserving therapy (BCT) was conducted in 22.1% of breast cancer patients in 1994 in Japan and is being performed with increasing frequency. According to the data already published, 10-27% of patients treated with BCT had a positive surgical margin. The recurrence rate in the breast is 1-2% annually, The 5-year overall survival in patients mostly consisting of stage I is 90% or higher at the present time. A case-control analysis of a multicenter study revealed that significant risk factors for breast recurrence were a positive surgical margin and absence of radiation therapy. Progress in basic research and diagnosis has also been instrumental in improving treatment results.

Incidence of p53 and Ha-ras gene mutations in chemically induced rat mammary carcinomas

To determine whether p53 alterations, which are frequent in human breast cancers, are also common in rat mammary tumors, we examined 40 tumors from 24 rats treated with 7,12-dimethylbenz[a]anthracene (DMBA) and 34 tumors from 14 rats treated with N-nitroso-N-methylurea (NMU) (an N-nitroso compound). DMBA and NMU are known genotoxic mutagens. The entire coding regions of the p53 and Ha-ras genes were examined for mutations by polymerase chain reaction single-strand conformational polymorphism analysis and by direct sequencing. One of the 40 DMBA-induced mammary tumors had a p53 mutation, a single-base substitution (AGC-->GGC) at codon 307, resulting in an amino-acid change from Ser to Gly. No mutations were found in NMU-induced tumors. The incidence of Ha-ras gene mutation was 79% (27 of 34) at codon 12 in the NMU group and 23% (nine of 40) at codon 61 in the DMBA group. Thus, p53 mutation, in contrast to Ha-ras mutation, did not seem to be a prerequisite for carcinogenesis in chemically induced rat mammary tumors.