Loss of heterozygosity on chromosome 11q13 in lobular lesions of the breast using tissue microdissection and polymerase chain reaction

Evaluating agreement, histological features, and relevance of separating pleomorphic and florid lobular carcinoma in situ subtypes

Morphological variants of lobular carcinoma in situ (LCIS) include classical (CLCIS), pleomorphic (PLCIS) and florid type (FLCIS). Treatment guidelines suggest managing PLCIS and FLCIS like ductal carcinoma in situ (DCIS); therefore accurate identification of LCIS subtypes is critical. However, the significance of separating PLCIS from FLCIS is not clear. Also, interobserver agreement in identifying LCIS subtypes, using contemporary criteria, is not known. We aimed to evaluate interobserver agreement amongst breast pathologists in diagnosing LCIS subtypes and use the agreement data to justify LCIS classification for management purposes. Six breast pathologists independently reviewed 50 hematoxylin and eosin-stained slides comprised of a mix of LCIS subtypes. After reviewing published criteria, participants diagnosed PLCIS, CLCIS and apocrine change in a marked region of interest and FLCIS based on entire section. PLCIS was identified in 8 to 37 slides with overall moderate agreement (Fleiss' κ = 0.565) and pairwise κ (Cohen's) ranging from -.008 to 0.492. FLCIS was diagnosed in 15-26 slides with overall substantial agreement (Fleiss' κ = 0.687) and pairwise κ ranging from -.068 to 0.706. Both FLCIS and PLCIS coexisted in 45% of slides with consensus on non-classical LCIS. Comedo-type necrosis (odds ratio = 5.5) and apoptosis (odds ratio = 1.8) predicted FLCIS. We found moderate and substantial agreement in diagnosing PLCIS and FLCIS respectively. Objective histological features linked with aggressive behavior were more frequent with FLCIS. PLCIS and FLCIS patterns frequently coexist, contain similar molecular aberrations, and are managed similarly (like DCIS); therefore, combining FLCIS and PLCIS into one category (non-classical LCIS) should be considered.

Wide local extension and higher proliferation indices are characteristic features of symptomatic lobular neoplasias (LNs) and LNs with an early invasive component

AIMS

Lobular neoplasias (LNs) are typically small, clinically undetectable breast lesions, but some LNs are of clinical significance. The aim of this study was to clarify the histopathological characteristics of clinically overt (symptomatic) LNs and early invasive LNs.

METHODS AND RESULTS

Sixty-two surgically resected LNs, including eight with early invasion (≤10 mm), were classified into the following groups: (i) symptomatic and occult; and (ii) early invasive and non-invasive. Six histopathological factors, including the Ki67 labelling index (LI), were assessed and analysed by logistic regression models. On multivariate analysis, tumour size (P = 0.008), mitotic counts (P = 0.006) and Ki67 LI (P = 0.035) were risk factors for symptomatic features, and tumour size (P = 0.009) and Ki67 LI (P = 0.015) were risk factors for early invasive lesions. In the eight LNs with invasion, the symptomatic and occult subgroups showed differing nuclear atypia and structural patterns, but both lesions extended widely (22-96 mm).

CONCLUSIONS

Wide extension and higher proliferation activity were characteristic features of symptomatic LNs and LNs with early invasion.

Biologic characteristics of premalignant breast disease

Breast cancer is the second leading cause of cancer death in women in the United States. While mammography and breast magnetic resonance imaging (MRI) improve detection of early disease, there remains an unmet need for biomarkers for risk stratification, early detection, prediction, and disease prognosis. A number of early breast lesions, from atypical hyperplasias to carcinomas in situ, are associated with an increased risk of developing subsequent invasive breast carcinoma. The recent development of genomic, epigenomic, and proteomic tools for tissue biomarker detection, including array CGH, RNA expression microarrays, and proteomic arrays have identified a number of potential biomarkers that both identify patients at increased risk, as well as provided insights into the pathology of early breast cancer development. This chapter focuses on the detection and application of tissue and serum biomarkers for the identification and risk stratification of early breast cancer lesions.

Breast-specific gamma imaging in the detection of atypical ductal hyperplasia and lobular neoplasia

RATIONALE AND OBJECTIVES

Atypical lesions such as atypical ductal hyperplasia (ADH) and lobular neoplasia are nonmalignant lesions that are associated with significant increased risk of developing breast cancer. Atypical lesions have been reported to present with focal increased radiotracer uptake on breast-specific gamma imaging (BSGI) examination, a novel physiologic tool for the detection of breast cancer. To date the sensitivity of BSGI in the detection of atypical lesions has not been reported. The purpose of this study is to determine the sensitivity of BSGI in detecting ADH and lobular neoplasia.

MATERIALS AND METHODS

A total of 1316 patients who received a BSGI exam between January 2006 and July 2009 were retrospectively reviewed. All patients who underwent minimally invasive biopsy and subsequent surgical excision where the highest pathology was solely ADH or lobular neoplasia (reported as ALH, lobular carcinoma in situ or lobular neoplasia), according to the pathology database were included (n = 15). The sensitivity was determined as the percentage of positive BSGI exams out of all patients diagnosed with ADH or lobular neoplasia who received a BSGI.

RESULTS

Patient ages ranged from 39 to 67 (mean, 52). Eight of 15 patients had ADH, 6/15 lobular neoplasia, and 1/15 ADH and lobular neoplasia in one lesion. Fifteen of the 15 (100%) patients with surgically confirmed ADH or lobular neoplasia had a positive BSGI, with focally increased radiotracer uptake at the site of the verified high-risk lesion.

CONCLUSION

BSGI has a high sensitivity for the detection of atypical, high-risk breast lesions. A diagnosis of an atypical lesion is concordant with focal increased radiotracer uptake with BSGI and can identify women at increased risk for breast cancer.

Lobular carcinoma in situ/atypical lobular hyperplasia on breast needle biopsies: does it warrant surgical excisional biopsy? A study of 27 cases

Lobular neoplasia including lobular carcinoma in situ (LCIS) and atypical lobular hyperplasia (ALH) may be identified in breast core needle biopsies as incidental findings or associated with microcalcifications. There are no general consensus guidelines for follow-up management in patients when lobular neoplasia is the only abnormal finding on core needle biopsy. The aim of this study was to evaluate our experience in the follow-up of these patients. A total of 3163 breast core needle biopsies were retrieved from the surgical pathology files between 2003 and 2009; among them, 56 (1.8%) cases were identified with a diagnosis of ALH or LCIS. Eleven cases were excluded because of the presence of a concurrent more severe lesion in the biopsies that mandated excision. The remaining 45 cases contained only ALH or LCIS and otherwise benign breast tissue; 27 had surgical excision follow-up. In the surgical excision specimens, 5 (19%) of 27 cases showed more severe lesions or were "upgraded" (3 invasive ductal carcinomas, 1 invasive lobular carcinoma, and 1 ductal carcinoma in situ). Histologic features of the lobular neoplasia on the cores, including association with microcalcifications, pagetoid involvement of ducts, and extensive lobular involvement, were retrospectively evaluated. These histologic features were found to have no predictive value for a more severe lesion in the subsequent excision. We suggest that patients with LCIS/ALH on core needle biopsy should be considered for surgical excision to rule out a more significant lesion regardless of the histologic features.

Is surgical excision necessary for the management of atypical lobular hyperplasia and lobular carcinoma in situ diagnosed on core needle biopsy?: a report of 38 cases and review of the literature

CONTEXT

Both atypical lobular hyperplasia (ALH) and lobular carcinoma in situ (LCIS) have traditionally been considered to be risk factors for the development of invasive carcinoma and are followed by close observation. Recent studies have suggested that these lesions may represent true precursors with progression to invasive carcinoma. Due to the debate over the significance of these lesions and the small number of cases reported in the literature, the treatment for lobular neoplasia diagnosed by percutaneous core biopsy (PCB) remains controversial.

OBJECTIVE

To review our experience with pure LCIS or ALH diagnosed by PCB and correlate the radiologic findings and surgical excision diagnoses to develop management guidelines for lobular neoplasia diagnosed by PCB.

DESIGN

We searched the pathology database for patients who underwent PCB with a diagnosis of either pure LCIS or ALH and had subsequent surgical excision. We compared the core diagnoses with the surgical excision diagnoses and the radiologic findings.

RESULTS

Thirty-eight PCBs with a diagnosis of ALH (18 cases) or LCIS (20 cases) were identified. Carcinoma was present at excision in 1 (6%) of the ALH cases and in 2 (10%) of the LCIS cases. In summary, 8% (3/38) of PCBs diagnosed as lobular neoplasia (ALH or LCIS) were upgraded to carcinoma (invasive carcinoma or ductal carcinoma in situ) at excision.

CONCLUSIONS

Surgical excision is indicated for all PCBs diagnosed as ALH or LCIS, as a significant percentage will show carcinoma at excision.

Genomics and premalignant breast lesions: clues to the development and progression of lobular breast cancer

Advances in genomic technology have improved our understanding of the genetic events that parallel breast cancer development. Because almost all mammary carcinomas develop in the terminal duct lobular units of the breast, understanding the events involved in mammary gland development make it possible to recognize those events that, when altered, contribute to breast neoplasia. In this review we focus on lobular carcinomas, discussing the pathology, development, and progression of premalignant lobular lesions from a genomic point of view. We highlight studies utilizing genomic approaches and describe how these investigations have furthered our understanding of the complexity of premalignant breast lesions.

Lobular Neoplasia: Is Surgical Excision Warranted?

The treatment of breast cancer associated with lobular neoplasia detected on core needle biopsy (CNB) remains controversial. The purpose of this study was to review the prevalence of lobular neoplasia in CNB specimens and to correlate CNB pathology to final surgical pathology. Patients with lobular neoplasia were included for analysis in this retrospective review. Patients with concomitant malignant or atypical lesions were excluded. Method of initial diagnosis, clinical history, pathology results, and follow-up data were then analyzed. From January 1994 to December 2005, 5257 CNBs were performed at our tertiary level medical facility. Of patients with lobular neoplasia, 42 of 50 (84%) patients had atypical lobular hyperplasia, whereas 8 (16%) patients were diagnosed with lobular carcinoma in situ on CNB specimens. There were no associated malignancies in 21 patients who underwent immediate surgical excision. Of those patients who were serially followed, four developed malignancies at an average of 73 months after the sentinel diagnosis. Three of the four (75%) malignancies occurred in the ipsilateral breast. Patients with a diagnosis of lobular neoplasia by CNB should not routinely undergo an open surgical biopsy. Lobular neoplasia should only be considered a risk marker for future invasive breast cancer.

The impact of large sections on the study of in situ and invasive duct carcinoma of the breast

Large histologic sections (LHSs) are increasingly used in the study of normal and neoplastic breast tissue. LHSs allow the direct visualization of a large part of the breast glandular tree. Accordingly, LHSs have shown that in situ and invasive lobular carcinoma is a multilobar (and hence multifocal) neoplastic lesion in more than 50% of the cases, and that poorly differentiated duct carcinoma in situ (DCIS grade 3) is frequently unifocal, whereas it is often multifocal when the in situ lesion is a well-differentiated type (DCIS grade 1). Forty-five mastectomies were studied with large sections. Mastectomies were performed when quadrantectomy did not guarantee radical excision of the tumor with adequate cosmesis because of the large size of the lesion or because the neoplastic lesion was located below the nipple. Excluded were cases of lobular neoplasia or invasive lobular carcinoma, because they were reported separately, and cases of mastectomies performed for sarcoma or recurrent phyllodes tumor. All cases had undergone a preoperative diagnostic procedure (fine needle aspiration), and the relative positive material was reviewed. All 45 cases showed in situ duct carcinoma and 37 showed evidence of invasive duct carcinoma. Forty-two cases of DCIS were multifocal, whereas only 4 invasive duct carcinoma were shown as multifocal. When DCIS lesions were subdivided into 3 grades, no statistical significance was seen among the 3 groups of DCIS in regard to multifocality. Nevertheless, DCIS grade 1 was a widespread condition involving more than one lobe and quadrant, whereas DCIS grades 2 and 3 appeared more localized. DCIS grade 1 was more similar to that previously observed in lobular in situ neoplasia/lobular in situ carcinoma. In 66.6% of the cases, DCIS foci were found within the invasive areas, indicating a more than fortuitous occurrence (2-sided P=.0357).

Expression of ER? and ER? in lobular carcinoma in situ

AIMS

Oestrogen is a modulator of cell growth and differentiation in the breast. It mediates most of its function through members of the oestrogen receptor (ER) family, ERalpha and ERbeta. Lobular carcinoma in situ (LCIS) is a known risk factor for the development of breast cancer; however, the use of tamoxifen for prevention is based upon data for ER+ (ERalpha) LCIS associated with invasion, but limited data exist on the use of tamoxifen in cases of ER+ (ERalpha) LCIS occurring in the absence of invasive carcinoma. The aim of this study was to examine ER expression in LCIS to determine the relationship of ERalpha to ERbeta and, thereby, to determine whether it is of clinical value to measure ERbeta along with ERalpha.

METHODS AND RESULTS

Core biopsy specimens from 50 patients were examined retrospectively. Histology was reviewed and histological parameters were assessed. Formalin-fixed paraffin-embedded tissue was available for E-cadherin, ERalpha and ERbeta immunohistochemistry. The degree of ERalpha and ERbeta nuclear reactivity was quantified. The patients' mean age was 55 years. The mean follow-up duration was 48 months. All 50 cases of LCIS were E-cadherin-negative. All cases were ERalpha+ and ERbeta+. The staining intensity of ERbeta was strong and included staining of periductal stromal cells. The median percentage of cells immunoreactive for ERalpha was 75% and for ERbeta 70% (range 10% weak positive to 100% strong positive). There was a statistically significant relationship between ERbeta staining intensity and incidence of ipsilateral breast cancer (P = 0.010).

CONCLUSIONS

The presence and intensity of both stromal and glandular ERbeta immunoreactivity suggest that the action of oestrogen on LCIS is on both stromal and glandular cells. Future studies are needed to determine whether the presence of ERbeta in LCIS could be targeted to influence the treatment of this disease and perhaps alter its natural history.

The Clinical Significance of Lobular Neoplasia on Breast Core Biopsy

A core biopsy diagnosis of atypical ductal epithelial hyperplasia is upstaged on follow-up excisional biopsy (FUEB) to in situ or invasive carcinoma in about 20% of cases, thus prompting a FUEB. In contrast, upstaging information for a core biopsy diagnosis of pure lobular neoplasia (LN), without mass lesions or other risk-associated lesions is less clear. In this retrospective study, we report the largest consecutive series of patients who had a breast core biopsy diagnosis of LN and a FUEB. Core needle breast biopsies with a diagnosis of LN were retrieved from our files for the period 1999 to 2005, yielding 110 patients. One hundred and one patients had a follow-up surgical excision. Cases of LN with coexisting high-risk lesions (n=9, 10%) were excluded from the study. Patients with associated mass lesions all had benign findings (n=15, 16%) and had no impact on the study results. The remaining 77 core biopsies had no masses or risk lesions and were mammographically Breast Imaging Reporting and Data System 4 (BIRADS) for microcalcifications. Overall, 8/77 (10%) of patients with a radiographic BIRADS 4 image with calcifications and a core biopsy diagnosis of LN on core biopsy were upstaged on FUEB to ductal carcinoma in situ or invasive carcinoma. The numbers upstaged from core biopsies were as follows: atypical lobular hyperplasia (ALH) 4/52 (8%), mixed ALH/lobular carcinoma in situ (LCIS) 1/9 (10%), and pure LCIS 3/16 (19%). A core biopsy of LCIS with neoplastic epithelial calcifications was nearly 3 times more likely to be upstaged on FUEB compared with ALH. We conclude that a finding of LN on breast core biopsy in a patient with a BIRADS 4 image and calcifications is associated with a risk of 8% to 19% of upstaging to a treatable disease on FUEB.

[Concepts and problems of lobular neoplasia]

The term lobular neoplasia (LN) includes lobular carcinoma in situ (LCIS) and atypical lobular neoplasia (ALH). It is generally considered to be a risk lesion and a non-obligatory precursor for the subsequent development of an invasive carcinoma in the ipsilateral or contralateral breast. LN has also been termed lobular intraepithelial neoplasia (LIN). A grading system (LIN 1-LIN 3) has been suggested as a tool for a more precise estimation of the individual risk. When LN is the most significant finding in a core biopsy, the probability of a higher grade lesion is about 17% in the follow-up surgical biopsy, justifying follow-up surgery in the majority of cases. A higher risk of progression is attributed to LIN 3 (pleomorphic LN, extensive LN, and signet ring cell LN) compared to LIN 1 or LIN 2. These special forms of LN may have an unusual presentation clinically or histologically. Using immunohistology, LN are characterized by the loss of E-cadherin, low proliferative activity and by positive hormone receptor status. The molecular characteristics of LN are similar to those of invasive lobular carcinomas, indicating the nature of LN as a precursor lesion.

Correlation between core biopsy and excisional biopsy in breast high-risk lesions

BACKGROUND

The purpose of the current study was to compare the prevalence of invasive or in situ cancer at excisional biopsy in patients with image-guided core needle biopsy (CNB)-proven atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), or lobular carcinoma-in-situ (LCIS). Factors affecting the upgrade rate to malignancy were also identified.

METHODS

Patients diagnosed with ADH, ALH, or LCIS on image-guided CNB (stereotactic or ultrasound) from 1995 to 2005 were identified through radiologic and surgical databases. Patients who subsequently underwent excisional biopsy of their lesion were included in the study. The imaging, medical records, and pathology of these patients were reviewed.

RESULTS

Ninety-six patients with either ADH (61/96, 63%), ALH (19/96, 20%), or LCIS (16/96, 17%) on image-guided CNB proceeded to excisional biopsy. Malignancy was detected on excisional biopsy in 31% of patients with ADH, 16% of patients with ALH, and 25% of patients with LCIS. There were no significant differences between the 2 groups in terms of age, parity, hormonal status, or previous benign breast biopsies. The presence of a mass on mammography was associated with an increased upgrade rate to malignancy, while biopsies performed using vacuum-assisted devices, larger gauge biopsy needles, and greater number of cores were associated with a lower upgrade rate.

CONCLUSIONS

Our data suggest that excisional biopsy is warranted in all patients with CNB diagnoses of ADH, ALH, or LCIS to exclude the presence of cancer.

The management of lobular carcinoma in situ (LCIS). Is LCIS the same as ductal carcinoma in situ (DCIS)?

Lobular carcinoma in situ was first described over 60 years ago. Despite the long history, it continues to pose significant difficulties in screening, diagnosis, management and treatment. This is partly due its multi-focal and bilateral presentation, an incomplete understanding of its biology and natural history and perpetuation of misconceptions gathered over the last decades. In this review, the working group on behalf of EUSOMA has attempted to summarise the current thinking and management of this interesting lesion.

Genetic similarities and differences between lobular in situ neoplasia (LN) and invasive lobular carcinoma of the breast

One of the most controversial issues in breast pathology is whether lobular neoplasia (LN) is a risk factor or a precursor lesion of invasive lobular carcinoma (ILC). This is consequent to the fact that no conclusive data on the biology of LN exist. Molecular studies of LN and ILC are scanty, variable, and not consistent. Clonality of 12 cases of LN and ILC present simultaneously in the same block has been studied. Cells from both lesions were obtained by microdissection and were studied for mitochondrial DNA (mtDNA), D-loop sequencing, and neighbor-joining trees. Eight of the same cases were studied with comparative genomic hybridization (CGH) array to have additional data consistent with mtDNA. In all cases, loss of heterozygosity was studied for D16S496,locus 16q22.1 related to e-cadherin. It appears that no fewer than eight cases were genetically very similar (clonal) with mtDNA. Seven of these cases appeared also clonal with CGH array. It is concluded that in the present series, LN and ILC are genetically related lesions in the majority of cases and that LN might be the precursor of ILC.

Biomarker profile and genetic abnormalities in lobular carcinoma in situ

The predisposition of patients with lobular carcinoma in situ (LCIS) to develop invasive breast cancer (IBC) is well known. However, relatively little is known about the biologic characteristics, which may be involved in the development and progression of LCIS. This study evaluated 59 cases of LCIS (29 pure, 30 with synchronous IBC) for five biomarkers known to be important in IBC (ER, PgR, c-erbB-2, p53 and Ki-67 proliferation rate) by immunohistochemistry. A comprehensive analysis of loss-of-heterozygosity (LOH) was performed in 12 cases (10 pure, 2 with synchronous IBC) at 15 genetic loci on 9 chromosomes. LCIS demonstrated a low grade/favorable biophenotype that was not significantly different in cases with and without synchronous IBC (ER 98%, PgR 84%, c-erbB-24%, p53 19% and proliferation rate 2%). LOH was present in 80% of pure LCIS and the highest rates of LOH were at loci on 9p (30%), 16q (63%), 17p (33%) and 17q (50%). The clustering of LOH at these four foci suggests that inactivated tumor suppressor genes in these regions may be particularly important. LOH was present in both cases of LCIS with synchronous IBC and the LOH phenotype was shared by LCIS and IBC. Our findings suggest that five known prognostic factors in IBC do not have prognostic utility in LCIS. Multiple genetic mechanisms may be involved in the development of LCIS.

Follow-up Surgical Excision Is Indicated When Breast Core Needle Biopsies Show Atypical Lobular Hyperplasia or Lobular Carcinoma In Situ

Atypical lobular hyperplasia (ALH) and lobular carcinoma in situ (LCIS) diagnosed in core needle biopsy (CNB) are generally regarded as risk indicators for developing invasive ductal or lobular carcinoma in either breast. Currently, there are no well-established guidelines for management of these patients. The most common management options are careful observation and endocrine chemoprophylaxis for high-risk patients. Previous studies had contradicting recommendations regarding follow-up surgical excision (FSE) of CNB yielding ALH or LCIS. These studies, unfortunately, have been limited by their retrospective nature, small number of patients examined, and association with other high-risk lesions. Only CNB diagnosed as pure LCIS or ALH (not associated with other high-risk lesions such as ADH, radial scar, or papilloma) were included in the study. We reviewed 33 CNB (20 ALH and 13 LCIS) with subsequent FSE from 33 patients (age range, 30-83 years; mean, 58 years). Eighteen of these patients were prospectively analyzed, where FSE was performed in an unselected fashion. All CNBs were obtained by mammotome (11-gauge, 30 cases; and 14-gauge, 3 cases). Mammography identified calcifications in 29 cases (88%) and a mass in 4 cases (12%). FSE revealed infiltrating ductal and/or lobular carcinoma in 4 of 13 LCIS (31%). FSE of 20 ALH revealed cancer in 5 cases (25%), including 4 ductal carcinoma in situ (DCIS) and 1 invasive lobular carcinoma. Seven of these nine cancers were associated with calcifications, and two presented as masses. Sampling error and underestimation of cancer (DCIS or invasive carcinoma) was associated with CNB diagnosis of LCIS or ALH in 27% of all cases. Underestimation of cancer was seen in 28% of prospectively examined patients, including 20% of ALH and 38% of LCIS. CNB associated with mass lesions or that showed histologic features of pleomorphic LCIS or extensive classic LCIS had a higher rate of cancer underestimation. Despite removal of all abnormal mammographic calcifications by CNB in 6 patients, one cancer was detected on FSE. To the best of our knowledge, this is the largest study reported to date, and the only one to include prospectively examined patients with no pre-selection bias. Our data strongly suggests that subsequent FSE is warranted in all patients with CNB diagnoses of LCIS or ALH, to exclude the presence of cancer.

Breast-conserving surgery and radiotherapy: a possible treatment for lobular carcinoma in situ?

Lobular carcinoma in situ (LCIS) is generally treated by conservative surgery alone and less often by mastectomy. We report our experience using conservative surgery and whole breast irradiation (WBI) for the treatment of patients with LCIS. From 1980 to 1992, 25 women with a median age of 54 years underwent lumpectomy (20) or quadrantectomy (5) and WBI (median dose: 52 Gy) for treatment of their LCIS. Five cases had palpable lesions, 19 were found by mammography alone and one case was found due to nipple discharge. Twelve women received tamoxifen at 20 mg/day for 2 years. With a median follow-up of 153 months (range 58-240), only one local recurrence was observed. The global rate of bilateral carcinoma was 17.6% (two synchronous and one metachronous). Until now, no case of LCIS treated by lumpectomy and radiation therapy has been reported in detail in the literature. After biopsy alone for LCIS, a subsequent infiltrating carcinoma occurs in approximately 15% of cases. Thus, classical radiosurgical therapy should represent an interesting alternative both for limited surgery alone and mastectomy, both of which have been proposed as sole treatments for LCIS.

Analysis of p53 mutations in cells taken from paraffin-embedded tissue sections of ductal carcinoma in situ and atypical ductal hyperplasia of the breast

Mutations in the p53 tumor suppressor gene are frequent in breast tumors but the implication of p53 mutations in breast cancer development remains poorly understood. In this study, we applied laser capture microdissection (LCM) microscope to histologically review and sample cells from paraffin-embedded breast tissue sections obtained from six cases of ductal carcinoma in situ (DCIS) and ten cases of atypical ductal hyperplasia (ADH). p53 mutations were detected, using single stranded conformational polymorphism (SSCP) and sequencing, in cell samples of three cases with DCIS and five cases with ADH. p53 mutations are therefore present in DCIS and ADH of the breast, considered as pre-malignant precursors to breast cancer, and some of them may represent early events in breast cancer development.

Large-scale mitochondrial DNA deletion mutations and nuclear genome instability in human breast cancer

Deletion mutations in mitochondrial (mt) DNA (mtDNA) as well as microsatellite instability (MSI) and loss of heterozygosity (LOH) in nuclear DNA (nDNA) exist in human cancer. We determined if: (1) large-scale mtDNA deletion mutations were present in cancerous and not in normal breast tissue, and (2) combining mt- and nDNA findings would provide complementary information to identify breast cancer. Thirty-nine matched breast cancer/histologically normal and 23 "true" normal tissue samples from women without breast cancer were microdissected and DNA extracted. 4977, approximately 3938, approximately 4388 and approximately 4576bp deletions were observed, with the 4576bp deletion being present in 0% of true normal, 13% of histologically normal specimens from a cancerous breast and 77% of breast cancers. The other three deletions were not specific to a breast containing cancer. LOH was found in 66.7% and MSI in 38.5% of samples. 38/39 (97.4%) tumors had at least one nDNA or 4576bp mtDNA alteration, suggesting that mt- and nDNA analysis provides complementary information in breast cancer detection. The 4576bp deletion appears to indicate cancer in the breast. The higher mtDNA copy number in cancer coupled with a mtDNA deletion mutation which appears specific for breasts which contain cancer may prove to be a good target to screen for cancer in the breast, including specimens of low and/or mixed cellularity.

The diagnosis and management of pre-invasive breast disease: genetic alterations in pre-invasive lesions

The development of modern molecular genetic techniques has allowed breast cancer researchers to clarify the multistep model of breast carcinogenesis. Laser capture microdissection coupled with comparative genomic hybridisation and/or loss-of-heterozygosity methods have confirmed that many pre-invasive lesions of the breast harbour chromosomal abnormalities at loci known to be altered in invasive breast carcinomas. Current data do not provide strong evidence for ductal hyperplasia of usual type as a precursor lesion, although some are monoclonal proliferations; however, atypical hyperplasia and in situ carcinoma appear to be nonobligate precursors. We review current knowledge and the contribution of molecular genetics in the understanding of breast cancer precursors and pre-invasive lesions.

Molecular and biologic markers of premalignant lesions of human breast

There is currently great interest in the detection and characterization of putative precursor breast cancer lesions because of the possibility of chemoprevention. Knowledge of the biologic features of premalignant lesions, although limited, is rapidly evolving. Premalignant breast lesions have been examined for the presence of genetic alterations and for the expression of biomarkers such as the estrogen receptor (ER), Ki67, p53, and HER2/neu. Data obtained from genetic studies of precursor breast lesions clearly support the contention that genetic alterations begin quite early in selected subsets of histologically benign lesions. Although the results of biomarker expression profiles have been contradictory, most studies agree that precursor lesions significantly overexpress ER and that progressive alterations in ER expression accompany the transition of normal cells to hyperplastic lesions and carcinoma in situ. So far, the collected evidence indicates that precursor lesions in the breast demonstrate biomarker expression profiles and genetic abnormalities that are distinct from those of terminal ductal lobular units but share some of these features with invasive tumors. Future research in this field is urgently needed to identify specific biomarkers of prognostic and predictive value, which can help not only in the selection of patients for chemopreventive therapy but in monitoring the progression of high-risk lesions.

Loss of heterozygosity and allelic imbalance in apocrine metaplasia of the breast: microdissection microsatellite analysis

Loss of heterozygosity (LOH) and allelic imbalance (AI) at loci reported to show allele loss and/or imbalance in preinvasive and invasive breast cancer were examined in 41 cases of apocrine metaplasia (APM) of the breast using a microdissection technique, polymorphic microsatellite markers, and the polymerase chain reaction (PCR). Occasional examples of LOH and/or AI were identified in 2/28 (7.1%) informative cases at 1p (MYCL1), 2/14 (14.3%) at 11q (INT2), 1/15 (6.7%) at 13q (D13S267), 3/22 (13.6%) at 16q (D16S539), 2/23 (8.7%) at 17p (TP53), and 1/11 (9.1%) at 17p (D17S513) and 3/16 (18.8%) at 17q (D17S250). The finding of LOH/AI in cases of APM indicates that a subset of APM appears clonal, but the significance of allelic loss or imbalance in the pathogenesis of APM or its possible subsequent progression to carcinoma is not yet clear and requires further investigation. Clinical follow-up of these particular cases of APM showing LOH/AI would be of further value.

Cholinesterase activity and acetylcholinesterase glycosylation are altered in human breast cancer

Increasing evidence supports the involvement of cholinesterases in tumorigenesis. Several tumour cells show ChE activity, while the acetyl- (AChE) and butyrylcholinesterase (BuChE) genes are amplified in leukemias, ovarian carcinoma and other cancers. ChE activity was measured in 31 samples of tumoral breast (TB) and 20 of normal breast (NB). Despite the wide variations observed, BuChE predominated over AChE both in TB and NB. The mean AChE activity in NB was 1.61 nmol of the substrate hydrolysed per minute and per miligram protein (mU/mg), which rose to 3.09 mU/mg in TB (p = 0.041). The BuChE activity dropped from 5.24 mU/mg in NB to 3.39 mU/mg in TB (p = 0.002). Glycolipid-linked AChE dimers and monomers and hydrophilic BuChE tetramers and monomers were identified in NB and TB, and their proportions were unmodified by the neoplasia. The amount of AChE forms reacting with wheat germ agglutinin (WGA) decreased in TB while that of BuChE species was unaffected, demonstrating that the glycosylation of AChE was altered in TB. The binding of AChE and BuChE with antibodies was unaffected by the neoplasia. The difference in lectin reactivity between erythrocyte and breast AChE, the lack of AChE in blood plasma, and the finding of monomeric BuChE in breast but not in plasma suggest that breast epithelial cells produce AChE for membrane attachment and hydrophilic BuChE for secretion. Several reasons are provided to explain the altered expression of ChEs in breast cancer.

Screening of selected genomic areas potentially involved in thyroid neoplasms

Loss of heterozygosity (LOH) studies have been used to identify sites harbouring tumour suppressor genes (TSGs) involved in tumour initiation or progression. To further elucidate the genetic mechanisms for follicular and papillary thyroid tumours development, we studied the frequency of LOH in 36 thyroid tumours (21 follicular thyroid adenomas (FAs) and 15 papillary thyroid carcinomas (PTCs)) on 10 specific genomic areas: 3p22, 3p25, 7q21, 7q31, 10q23, 10q25-26, 11q13, 11q23, 13q13 and 17p13.3-13.2 using 20 polymorphic markers. We have selected these areas for two reasons: (a) Even though LOH in thyroid neoplasms has been described in some of these areas, results are controversial, and (b) we have also studied areas described as involved in other epithelial or endocrine tumour types, but not studied up to now in thyroid neoplasms. Two areas showed a high percentage of LOH: 7q31 and 11q23. A 62% LOH was found at 7q31 in the FAs, suggesting, as other authors have proposed, that at least one TSG must be present in the vicinity of the c-met locus. The second area in frequency was at the 11q23 locus, with a 45% LOH in the FAs. This area was studied because it has been described as being involved in the development of epithelial and endocrine cancers. This locus had not been studied before in thyroid neoplasms. This result is interesting because the LOH11CR2A gene is localised at this locus. We suggest that this gene and/or an other TSG nearby may be involved in the progression to FA. In our study, a low percentage of LOH was found in the PTC samples, indicating that TSGs present in the areas we have studied are not significantly involved in their progression. Our data also suggest that TSGs located in areas where no LOH was detected (PTEN, MEN1, Cyclin D1, BRCA2 and RFC3) are not involved or do not have an important role in tumour progression.

Molecular genetics of solid tumours: translating research into clinical practice. What we could do now: breast cancer

Breast cancer is a common solid malignancy in women. Over the past decade, much progress has been made in understanding the biology of breast cancer. The use of molecular and immunohistochemical techniques is providing insights that will allow us to tailor the management of patients with breast cancer. In this review, progress in the understanding of lobular carcinoma in situ and atypical ductal hyperplasia, the use of the molecular marker CerbB2, and information gained from the morphological analysis of tumours arising in patients with BRCA1 and BRCA2 mutations is discussed.

Lobular carcinoma in situ and infiltrating ductal carcinoma: frequent presence of DCIS as a precursor lesion

Infiltrating ductal carcinoma (IDC) occurs frequently in patients with lobular carcinoma in-situ (LCIS). LCIS is not thought to be the direct precursor of the invasive component. The authors analyzed 15 cases of coexisting LCIS and IDC and found ductal carcinoma in situ (DCIS) in 12. The DCIS and IDC were of similar grade and located in the same area. Selected cases stained with E-cadherin demonstrated a different immunophenotype for the lobular and ductal lesions. These results support the notion that DCIS is the direct precursor of IDC occurring in patients with LCIS.

New developments in the analysis of gene expression

An understanding of the relationship between gene expression, protein expression and the influences of genetic responses upon gene function is vital before we can understand the complexity of genomes. Traditional methods for the study of gene expression are limited to studying small groups of genes at a time and a source of pure starting material has been difficult to obtain. Recent technological advances have enabled large numbers of genes, from specific cell populations, to be studied in a single experiment. Laser capture microdissection (LCM) and microarray technology are providing the next revolution in the study of gene expression. LCM-based molecular analysis of histopathological lesions can be applied to any disease process that is accessible through tissue sampling. Examples include: (i) mapping the field of genetic changes associated with oxidative stress; (ii) analysis of gene expression patterns in atherosclerotic tissues, sites of inflammation and Alzheimer's disease plaques; (iii) infectious micro-organism diagnosis; and (iv) typing of cells within disease foci. Microarray hybridisation glass chips spotted with sets of genes can then be used to obtain a molecular fingerprint of gene expression in the microdissected cells. The variation of expressed genes or alterations in the cellular DNA that correlate with a particular disease state can be compared within or between individual samples. The identification of gene expression patterns may provide vital information for the understanding of the disease process and may contribute to diagnostic decisions and therapies tailored to the individual patient. Molecules found to be associated with defined pathological lesions may provide clues about new therapeutic targets in the future.

Deletion of the FHIT gene in neoplastic and invasive cervical lesions is related to high-risk HPV infection but is independent of histopathological features

The fragile histidine triad (FHIT) gene encompasses the common chromosomal fragile site FRA3B. Human papilloma virus (HPV), which is the main aetiological agent in cervical cancers, has been found to be able to integrate its genes into the chromosome 3 fragile site of cultured cells, deleting a piece of DNA which includes the FHIT gene. Eighty-six microdissected archival cervical LLETZ biopsies comprising cases of cervical intraepithelial neoplasia (CIN) 1 (n=27), CIN3 (n=30) and microinvasive carcinoma (n=29) were evaluated for HPV infection and FHIT gene loss of heterozygosity (LOH). FHIT gene LOH was detected by polymerase chain reaction (PCR) using fluorescently labelled intragenic microsatellite markers D3S1300 and D3S4103. PCR products were analysed on a semi-automated DNA sequencer using Fragment Manager(trade mark) software to determine allele loss. The HPV status of the lesions was determined by PCR using generic and type-specific primers in conjunction with restriction endonuclease digestion. The results were analysed using Epi-Info and SPSS-PC statistical analysis software. Haematoxylin and eosin-stained sections from the 86 cases were profiled for six histopathological features, some of which have been previously shown to be associated with microinvasive cancer. FHIT gene LOH was found in 36% of CIN1 cases, 52% of CIN3 cases and 73% of microinvasive cases (p=0.029). HPV 16 DNA was found in 68% of CIN3 cases and 93% of microinvasive cases (p<0.001). The second most prevalent HPV type found was HPV 31, which was present in only four lesions, three of which had FHIT gene LOH. When FHIT gene LOH was evaluated versus HPV 16 and 31 infection using the chi-square test, a statistically significant relationship was found (p=0.014). FHIT gene LOH was found to be independent of the histopathological features evaluated. The finding of a statistically significant relationship between FHIT gene LOH and oncogenic HPV infection suggests a link between the integration of viral DNA and subsequent gene deletion in the progression of cervical cancer. FHIT gene anomalies may prove to be excellent markers of progression in early uterine cervical cancers.

Deletion of the FHIT gene in neoplastic and invasive cervical lesions is related to high-risk HPV infection but is independent of histopathological features

The fragile histidine triad (FHIT) gene encompasses the common chromosomal fragile site FRA3B. Human papilloma virus (HPV), which is the main aetiological agent in cervical cancers, has been found to be able to integrate its genes into the chromosome 3 fragile site of cultured cells, deleting a piece of DNA which includes the FHIT gene. Eighty-six microdissected archival cervical LLETZ biopsies comprising cases of cervical intraepithelial neoplasia (CIN) 1 (n=27), CIN3 (n=30) and microinvasive carcinoma (n=29) were evaluated for HPV infection and FHIT gene loss of heterozygosity (LOH). FHIT gene LOH was detected by polymerase chain reaction (PCR) using fluorescently labelled intragenic microsatellite markers D3S1300 and D3S4103. PCR products were analysed on a semi-automated DNA sequencer using Fragment Manager(trade mark) software to determine allele loss. The HPV status of the lesions was determined by PCR using generic and type-specific primers in conjunction with restriction endonuclease digestion. The results were analysed using Epi-Info and SPSS-PC statistical analysis software. Haematoxylin and eosin-stained sections from the 86 cases were profiled for six histopathological features, some of which have been previously shown to be associated with microinvasive cancer. FHIT gene LOH was found in 36% of CIN1 cases, 52% of CIN3 cases and 73% of microinvasive cases (p=0.029). HPV 16 DNA was found in 68% of CIN3 cases and 93% of microinvasive cases (p<0.001). The second most prevalent HPV type found was HPV 31, which was present in only four lesions, three of which had FHIT gene LOH. When FHIT gene LOH was evaluated versus HPV 16 and 31 infection using the chi-square test, a statistically significant relationship was found (p=0.014). FHIT gene LOH was found to be independent of the histopathological features evaluated. The finding of a statistically significant relationship between FHIT gene LOH and oncogenic HPV infection suggests a link between the integration of viral DNA and subsequent gene deletion in the progression of cervical cancer. FHIT gene anomalies may prove to be excellent markers of progression in early uterine cervical cancers.

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.

Genetic relation of lobular carcinoma in situ, ductal carcinoma in situ, and associated invasive carcinoma of the breast

AIMS

The mutual relation of lobular carcinoma in situ (LCIS) and ductal carcinoma in situ (DCIS) of the breast, as accepted precursor lesions of invasive breast cancer, is controversial. Because they display genetic heterogeneity, it is not clear how genetically advanced these entities are and what causes the transition to an invasive carcinoma.

METHODS

Six cases of LCIS, four of them with associated lobular invasive carcinoma, four cases of intermediately differentiated DCIS with an associated invasive lobular carcinoma, and nine cases of intermediately and poorly differentiated DCIS with associated ductal invasive carcinoma were investigated by means of comparative genomic hybridisation (CGH) after microdissection and immunohistochemical staining of E-cadherin.

RESULTS

LCIS was characterised by a low average rate of copy number changes, no evidence of amplifications, and a high rate of gains and losses of chromosomal material at 1q and 16q, respectively. A high degree of genetic homology with well differentiated DCIS was obvious, as reported previously. The cases of intermediately differentiated DCIS with associated lobular invasive components and lobular differentiation revealed striking homologies, and a significant difference of E-cadherin expression. The comparison of preinvasive and invasive breast lesions, irrespective of differentiation within the same patient, revealed no specific alteration that might be associated with invasion. Genetic alterations seen in invasive carcinoma were not necessarily seen in the adjacent precursor lesions.

CONCLUSIONS

These results provide strong evidence that invasive breast cancer is a disease with multiple cytogenetic subclones already present in preinvasive lesions. Moreover, specific CGH alterations associated with invasion were not observed. Furthermore, the close genetic association between well differentiated and a subgroup of intermediately differentiated DCIS and LCIS led to the hypothesis that LCIS and a subgroup of DCIS are different phenotypic forms of a common genotype.

Mammaglobin, a potential marker of breast cancer nodal metastasis

The Mammaglobin gene, a breast-specific member of the uteroglobin gene family, has been previously identified as being overexpressed in some breast tumours, but the cellular origin and relationship to tumour progression are unknown. Using a subtractive hybridization approach, mammaglobin mRNA has also been found to be overexpressed in the in situ compared to the invasive element within an individual breast tumour. Further study by in situ hybridization performed in 13 breast tumours, selected to include normal, in situ, and invasive primary tumour elements, and in most cases axillary lymph node metastases, revealed that mammaglobin expression occurs in all elements, is restricted to epithelial cells, and is significantly increased in tumour cells compared with normal cells ( p< 0.04). Analysis of mammaglobin expression within 20 independent primary breast tumours and their corresponding axillary lymph nodes revealed that all 13 lymph nodes positive and none of the seven nodes negative for metastatic breast carcinoma by histology were mammaglobin-positive by reverse transcription-polymerase chain reaction (RT-PCR) ( p=0.0001). These results suggest that mammaglobin could be a marker of axillary lymph node breast metastases.

Atypical lobular hyperplasia and lobular carcinoma in situ: surgical and molecular pathology

Lobular carcinoma in situ and atypical lobular hyperplasia were first described over 50 years ago. Despite this long incubation period, the biological nature of the lesions remains controversial. They are generally regarded as 'risk indicators' of invasive cancer rather than true precursor lesions. When first described, the 'carcinoma in situ' designation implied radical treatment in the form of a mastectomy. Subsequent observation has shown that the lesions are often multifocal and bilateral. The risk to the woman of developing invasive cancer after a diagnosis of lobular carcinoma in situ is small. Hence, the lesion has increasingly been regarded as a 'hyperplastic' proliferation, which although predicting for subsequent risk of invasive cancer, does not in itself need treatment. In this review, we challenge this view and explore the developments in the understanding of this controversial entity.

Experimental pathology and breast cancer genetics: new technologies

The goal is to understand the critical events in tumour development and to apply this understanding to new approaches to diagnosis, prevention and treatment. It is clear that breast cancer is a heterogeneous disease at the molecular level, raising the possibility of a future functional classification based on mechanisms rather than morphology. These molecular phenotypes will also confer predictive value on the potential of the tumour to invade, metastasise and respond to or resist new therapeutic strategies. Studies of the genome in individuals are predicted also to enable the identification of polymorphisms that are associated with increased susceptibility to environmental factors, in addition to possibly explaining de novo variations in responses to drugs and radiation. The difficulty is how to identify which, of the approximately 30,000 genes expressed by a typical cancer cell alone or in combination, are the ones involved in these processes. The majority of breast cancers have such a multitude of molecular changes that it is difficult to distinguish between those that are critical to tumour progression and those that are epiphenomena of genetic instability and abnormalities in DNA repair. The identification of the earliest events in carcinogenesis must be the best hope, as it will then be possible to target the events that predispose to other secondary changes before they occur. Genomics and proteomics is the current hope to take us forward. This involves the application of a number of new technologies to facilitate the profiling of individual tumours, including laser-guided microdissection of microscopic lesions, comparative genomic hybridisation and loss of heterozygosity analysis of DNA using microarray technology to study DNA and expressed RNAs and protein profiling using 2D gel mass spectroscopy. With over 100,000 mRNAs and proteins to examine in complex tissues and in various combinations, there is obviously going to be a requirement for a large investment in computing power (bioinformatics) to facilitate the analysis of these data in relation to the clinical characteristics of the individual tumour and the patient.

The transition from hyperplasia to invasive carcinoma of the breast

The multistep model of carcinogenesis in the breast suggests a transition from normal epithelium to invasive carcinoma via non-atypical and atypical hyperplasia and in situ carcinoma. Within the breast, these proliferations are heterogeneous in their cytological and architectural characteristics. This review considers the evidence supporting a precursor role for these preinvasive lesions.

Chromosomes, 11Q and cancer: a review

This review aims at providing a general understanding of how the multiple cytogenetic aberrations in cancer cells arise and exemplifies this by considering the specific role of chromosome 11q loci in carcinogenesis. Section I provides a theoretical molecular and structural framework for understanding the cytogenetic aberrations described in cancer. Given this background, Section II describes advances in the identification and localization of cancer susceptibility genes on chromosome 11q, highlighting ongoing areas of investigation.

A 500-kb sequence-ready cosmid contig and transcript map of the MEN1 region on 11q13

We have generated a transcript map of an approximately 1.2-Mb region from human chromosome band 11q13 between the loci VEGFB and CAPN1, which flank the multiple endocrine neoplasia type 1 (MEN 1) locus. In total, we isolated 144 cosmids from this region and generated a sequence-ready cosmid contig of the approximately 500-kb region between the neurexin locus and D11S2196E. We identified 54 genes/ESTs by sample sequencing and have constructed a transcript map of this region. Genes were found to be clustered in three regions, and one of these genes was identical to the recently identified MEN1 locus. Relative to the latter, we have mapped the positions of 13 known genes, 18 genes which show homology to genes from humans or other organisms, and 22 genes/ESTs that appear novel. In addition, we have ascertained the directions of transcription of some of these genes and have determined intergenic distances between many loci. Full characterization of some of these genes, as well as the novel ESTs, will be useful in identifying candidate genes for other diseases known to map to this chromosomal region.

Analysis of loss of heterozygosity in 399 premalignant breast lesions at 15 genetic loci

BACKGROUND

Usual ductal hyperplasia (UDH), atypical ductal hyperplasia (ADH), and ductal carcinoma in situ (DCIS) are risk factors for invasive breast cancer (IBC), suggesting that these lesions may be direct precursors of IBC. To identify genetic changes that may be important in the early development of precursor lesions and their progression to malignant or invasive disease, we examined 399 putative precursors (211 UDH, 51 ADH, 81 non-comedo DCIS, and 56 comedo DCIS) for loss of heterozygosity (LOH) at 15 polymorphic genetic loci known to exhibit high rates of loss in IBC. We also assessed the sharing of LOH by putative precursors and synchronous cancers.

METHODS

The polymerase chain reaction was used to analyze DNA from microdissected archival specimens.

RESULTS AND CONCLUSIONS

In hyperplasias from noncancerous breasts (i.e., without DCIS and/or IBC in analyses of hyperplasias), LOH at any given locus was rare (range, 0%-15%), although 37% of UDH and 42% of ADH lesions showed loss for at least one locus, suggesting that the development of hyperplasias can involve many different tumor suppressor genes. In DCIS from noncancerous breasts (i.e., without IBC in analyses of DCIS), LOH was common, with 70% of noncomedo lesions and 79% of comedo lesions showing at least one loss. In DCIS, substantial rates of loss (up to 37%) were observed at loci on chromosomes 16q, 17p, and 17q, suggesting that inactivated tumor suppressor genes in these regions may be important in the development of noninvasive breast cancer. When DCIS lesions from cancerous and noncancerous breasts were compared, substantially more LOH was observed in the cancerous breasts at a few loci (on chromosomes 2p, 11p, and 17q), suggesting that genetic alterations in these regions may be important in the progression to invasive disease. Among specimens harvested from cancerous breasts, 37% of UDH, 45% of ADH, 77% of noncomedo DCIS, and 80% of comedo DCIS lesions shared LOH with synchronous cancers at one locus or more, supporting the idea that the putative precursors and the cancers are genetically related.