Histopathological and clonal study of combined lobular and ductal carcinoma of the breast

Lobular carcinoma in situ (LCIS) clinically constitutes a risk factor for the subsequent development of either invasive lobular carcinoma (ILC) or invasive ductal carcinoma (IDC). In order to approach the possibility of this common precursor of both ILC and IDC, we investigated combined lobular and ductal carcinomas. Thirty‐two cases of lobular carcinoma were picked up out of 773 cases of operated breast carcinomas. The histopathological detailed re‐examination using immunostain of E‐cadherin and β‐catenin revealed a rather high frequency of combined lobular carcinomas than previous reports. Clinicopathologically, combined lobular carcinomas were younger and smaller than pure lobular carcinomas, and the cytological atypia was relatively low. These results suggested that combined lobular carcinomas could be detected in the earlier stage of breast cancer. Furthermore, the lobular and ductal components of combined carcinomas coexisted in the neighborhood and were distributed contiguously. The immunohistochemical phenotypes of both components were accorded in most combined cases. A genetic analysis using methylation‐specific PCR on the HUMARA gene demonstrated that the same allele was inactivated in both lobular and ductal components in all detectable cases of combined carcinoma. Therefore, it is reasonable to assume that both lobular and ductal components of combined carcinomas are clonal and derived from the LCIS as the common precursor lesion, which may contradict the conventional concept that the lobular and ductal carcinomas arise from distinct differentiation pathways.     

Tubular carcinoma of the breast and associated intra-epithelial lesions: a comparative study with invasive low-grade ductal carcinomas

Ductal intra-epithelial lesions of the breast are associated with invasive neoplasms and comprise a large spectrum of histological patterns. We have examined 23 cases of pure tubular carcinomas (TCs) of the breast and 53 cases of invasive ductal low-grade carcinomas to determine the relationship and distribution of intra-epithelial lesions, mainly of ductal in situ carcinoma type, but including also lobular intra-epithelial neoplasia (LIN) in both entities. Eleven cases of TC showed flat epithelial atypia (FEA) (47.8%), and, in 14 and 6 cases, micropapillary and cribriform low-grade ductal carcinoma in situ (DCIS) were present (60.7 and 26.1%, respectively). On the opposite, in ductal grade I invasive carcinomas, the most frequent architectural pattern was low-grade DCIS growing in arcades in 26 cases (49%). While absent in TCs, low-grade DCIS of solid type was found in five (9.4%) cases of ductal invasive carcinomas, where FEA were present in seven (13.2%) cases. LIN lesions were present in four (17.4%) cases of TC, whereas they represented 7.5%, as reported by Carstens et al. (Am J Clin Pathol 58:231–238, 1972), of cases of low-grade carcinomas. These results suggest that invasive pure TC and low-grade ductal carcinomas of the breast are different lesions, and support the fact that TC, of low histopathological grade, is a particular distinct tumoural entity.     

PIK3CA mutation and histological type in breast carcinoma: high frequency of mutations in lobular carcinoma

Mutations in the PIK3CA gene have recently been reported in different human neoplasms, including breast cancer. This paper reports the results of a systematic analysis of PIK3CA mutations in different histological types of breast carcinoma. One hundred and eighty invasive breast carcinomas, comprising 74 ductal, 56 lobular, 22 mucinous, 20 medullary, and eight papillary, were selected on the basis of their histological type in a consecutive series of 780 breast cancers. Exons 1-20 of the PIK3CA gene were subjected to SSCP analysis followed by direct sequencing. PIK3CA mutations were observed in 46 (26%) of the 180 tumours examined: 23 (50%) mutations were located in exon 9, and 23 (50%) in exon 20. Mutations were frequent in lobular (46%), less frequent in ductal (22%), and uncommon in medullary (10%), mucinous (5%), and papillary tumours (12%) (p = 0.0002). Mutations in exon 9 were more frequent in lobular carcinomas (30% of cases) than in the other histological types (less than 5% of cases) (p = 0.00014). No significant differences were observed in the distribution of mutations in exon 20. There was no significant correlation between PIK3CA mutations and other clinicopathological and biological variables, including age, tumour size, lymph node metastases, oestrogen receptor (ER) status, progesterone receptor (PgR) status, p53 gene mutations, and p53 protein expression. The findings indicate that in invasive breast carcinomas, PIK3CA alterations are mainly present in lobular and ductal tumours, whereas the other histological types, known to be associated with a favourable prognosis, show a very low incidence of PIK3CA mutations.     

Expression of E-cadherin and c-erbB-2/HER-2/neu oncoprotein in high-grade breast cancer

E-cadherin (E-CD) is an epithelial-specific cell adhesion molecule, whose expression is lost in invasive lobular (ILC) but not in invasive ductal carcinoma (IDC) of the breast. This cell adhesion system can be disrupted by tyrosine kinase c-erbB-2/HER-2/neu. We examined 106 cases of high-grade invasive breast cancer, including 91 IDCs, 12 ILCs and 3 pleomorphic lobular carcinomas (PLCs). We determined Nottingham histological grade and performed immunohistochemistry for estrogen and progesterone receptors (ER/PR), Ki-67, E-CD and c-erbB-2/HER-2/neu with subsequent fluorescence in situ hybridization. Amplification of c-erbB-2/HER-2/neu gene was observed in 55/91 (60.4%) of IDCs, 3/12 (25%) of ILCs and 1/3 (33.3%) of PLCs, and associated with positive axillary lymph nodes. E-CD expression was lost in 14/91 (15.4%) of IDCs, 10/12 (83.3%) of ILCs and 2/3 (66.7%) of PLCs. The loss of E-CD immunoreactivity in IDCs appeared to be associated with c-erbB-2/HER-2/neu gene amplification, negative ER/PR status and positive lymph nodes, whereas E-CD-positive ILCs tended to be HER-2/neu-positive. The biological significance of E-CD expression seems to be different in high-grade IDC and ILC. Oncogenic pathway mediated by c-erbB-2/HER-2/neu may affect the E-CD expression in most invasive ductal breast carcinomas in vivo.     

E-cadherin status in breast cancer correlates with histologic type but does not correlate with established prognostic parameters

Our objective was to assess the loss of E-cadherin (EC) as a diagnostic marker or a predictor of prognosis. We stained 276 breast carcinomas with monoclonal antibodies to EC (invasive lobular carcinomas [ILC] and variants, 59; invasive ductal carcinoma and ductal special types [IDC], 204; tubulolobular carcinoma [TLC], 4; and invasive carcinoma [IC], uncertain whether lobular or ductal type, 9). The results were as follows: EC+IDCs, 99.5%; EC-ILCs, 90%; EC+ILCs, 10%; EC+pleomorphic ILCs, 20%; EC-ICs, 44%. All 4 TLCs showed positive tubules while cords were negative. Statistically a correlation of EC loss with a positive diagnosis of ILC was found but there was no correlation with any prognostic tumor variables. A negative EC stain confirms the diagnosis of ILC (specificity, 97.7%; negative predictive value, 96.8%; sensitivity, 88.1%; positive predictive value, 91.2%). EC is helpful in classifying cases with indeterminate histologic features. EC loss is uncommon in nonlobular carcinomas with no correlation to currently established prognostic variables.     

Epithelial (E-) and placentae (P-) cadherin cell adhesion molecule expression in breast carcinoma

Two members of the cadherin family of intercellular adhesion molecules are found in normal breast tissue: E- (epithelial) cadherin is present in both luminal and myoepithelial cells, whereas P- (placental) cadherin is confined to myoepithelium. There is experimental evidence that loss of E-cadherin is associated with increased invasiveness of malignant cells in vitro, which stimulated us to examine the presence and distribution of E- and P-cadherin in breast carcinomas by means of immunohistochemical staining. E-Cadherin was present in all in situ and invasive ductal carcinomas examined, although it had a patchy distribution and the staining was of variable intensity. However, in 83 per cent of invasive lobular carcinomas and all lobular carcinomas in situ there was complete loss of E-cauherin expression. In the remaining 17 per cent of invasive lobular tumours, E-cadherin appeared to have an abnormal distribution within the cytoplasm with variable expression on the cell membrane. P-Cadherin, by contrast, was absent from all benign breast luminal epithelium and 25 carcinomas of ductal and lobular type. It was found in only one carcinoma of lobular type. We suggest that loss of cell-cell adhesion mediated by E-cadherin plays a part in the characteristic morphology of lobular carcinomas.     

Epithelial atypia in biopsies performed for microcalcifications. Practical considerations about 2,833 serially sectioned surgical biopsies with a long follow-up

This study analyzes the occurrence of epithelial atypia in 2,833 serially sectioned surgical breast biopsies (SB) performed for microcalcifications (median number of blocks per SB:26) and the occurrence of subsequent cancer after an initial diagnosis of epithelial atypia (median follow-up 160 months). Epithelial atypia (flat epithelial atypia, atypical ductal hyperplasia, and lobular neoplasia) were found in 971 SB, with and without a concomitant cancer in 301 (31%) and 670 (69%) SB, respectively. Thus, isolated epithelial atypia were found in 670 out of the 2,833 SB (23%). Concomitant cancers corresponded to ductal carcinomas in situ and micro-invasive (77%), invasive ductal carcinomas not otherwise specified (15%), invasive lobular carcinomas (4%), and tubular carcinomas (4%). Fifteen out of the 443 patients with isolated epithelial atypia developed a subsequent ipsilateral (n = 14) and contralateral (n = 1) invasive cancer. The high slide rating might explain the high percentages of epithelial atypia and concomitant cancers and the low percentage of subsequent cancer after a diagnosis of epithelial atypia as a single lesion. Epithelial atypia could be more a risk marker of concomitant than subsequent cancer.     

Tumor type and single-cell/mesothelial-like cell pattern of breast carcinoma metastases in pleural and peritoneal effusions

Invasive ductal and lobular breast carcinomas often have different preferred metastasis sites and distinct histomorphologic characteristics. Their metastatic cytomorphologic cell features in body cavity fluids are generally readily recognized, but the single-cell/mesothelial-like pattern and its relationship to the primary tumor type have not been well studied, nor whether metastases have a propensity for certain body cavity sites on the basis of the primary tumor type. To further assess the tumor type and single-cell pattern of breast carcinoma metastases in pleural and peritoneal effusions, we retrospectively studied 853 pleural and peritoneal effusions and correlated the findings with the primary tumor type. When necessary, the single- cell/mesothelial-like pattern was documented immunohistochemically. Metastatic breast carcinomas represented 249 (50.8%) of 490 pleural and 51 (14.0%) of 363 peritoneal effusions. Most metastases in pleural and peritoneal effusions were ductal carcinomas (92.4% and 62.7%, respectively). Lobular carcinoma accounted for only 2 (0.8%) of 249 pleural and 11 (21.6%) of 51 peritoneal effusions. The single-cell/mesothelial-like cell pattern was found in all lobular carcinomas but also in 11 (6.0%) of 184 reviewed ductal carcinomas (nine pleural and two peritoneal). Awareness of these findings and the use of immunohistochemical analyses are necessary for accurately diagnosing metastatic breast carcinoma, especially lobular type.     

Pleomorphic lobular carcinoma of the breast: its cell kinetics, expression of oncogenes and tumour suppressor genes compared with invasive ductal carcinomas and classical infiltrating lobular carcinomas

AIMS: The study addresses whether pleomorphic lobular breast carcinomas represent a distinct entity with respect to proliferation and apoptosis as well the expression of the p53, bcl-2 and Her2 protein. METHODS AND RESULTS: The study included 30 cases of pleomorphic lobular carcinoma (PLC; G2 n=15, G3 n=15). Poorly differentiated invasive ductal carcinomas (IDC; n=15) and well-differentiated infiltrating lobular carcinomas (ILC; n=15) were used as controls. Lymph node metastases were present equally in all groups. MIB-1 labelling was counted as: PLC (G2) 8.36%; PLC (G3) 11.3%; IDC 44.26%; ILC 2.19% (P=0.0001, P=0.004, P=0.001). Apoptotic index was: PLC (G2) 0.82%; PLC (G3) 1.2%; IDC 2.09%; ILC 0.6% (P=0.009, P=0.001). Over-expression of Her2 protein was detected in 53% of PLC (G3) tumours and was present only in scattered cases in the other groups. PLCs and ILCs were strongly positive for bcl-2 and for hormone receptors, while p53+ cells were rare. IDCs exhibited a heterogeneous staining pattern for bcl-2 and for hormone receptors, while p53+ cells occurred considerably more frequently. Stage could not be linked directly to proliferation or apoptosis. CONCLUSION: Our data suggest that more frequent over-expression of Her2 among PLCs (G3) as well as the generally low apoptosis can contribute to their aggressive behaviour.     

Paucity of fibronectin in invasive lobular carcinoma of breast

Fifty-four cases of invasive carcinoma of breast were immunostained for fibronectin and laminin. They included 36 cases of invasive ductal carcinoma and 18 cases of invasive lobular carcinoma. Although there was some heterogeneity within tumours, it was found that whilst the majority of ductal carcinomas (31/36) had abundant fibronectin at cell/stroma boundaries or diffusely throughout stroma, a substantial proportion of lobular carcinomas (12/18) had very little (P less than 0.001). This difference could not be related to differences in laminin immunoreactivity, which was most commonly scanty or absent in both tumour types. It is postulated that the characteristic infiltration pattern of lobular carcinoma may be attributed in part to paucity of stromal fibronectin.     

Correlation of HER2 overexpression with gene amplification and its relation to chromosome 17 aneuploidy: a 5-year experience with invasive ductal and lobular carcinomas

The HER2 oncogene shows expression or amplification, or both, in approximately 15% to 20% of breast cancers and has been associated with poor prognosis and a response to trastuzumab therapy. HER2 gene status determines the eligibility of breast cancer patients for trastuzumab therapy and a large fraction (41-56%) of these patients respond to targeted therapy. Several studies have related the increased expression of HER2 to an increased copy number of chromosome 17, rather than amplification of the HER2 gene. We compared the results of immunohistochemistry and fluorescence in situ hybridization in both invasive ductal and invasive lobular carcinomas, to determine the frequency of chromosome 17 aneuploidy associated with discordant results. In total, 390 invasive ductal carcinomas and 180 invasive lobular carcinomas diagnosed from January 2000 to December 2005 were included in the study only if results were available for immunohistochemistry (HercepTest; DAKO, Carpinteria, California) and fluorescence in situ hybridization (PathVysion HER2 DNA Probe Kit; Abbott Laboratories, Des Plaines, Illinois). Tumors classified as invasive ductal carcinomas were graded according to the Bloom-Richardson grading system. Correlation between the results of immunohistochemistry and fluorescence in situ hybridization was performed for all categories. Among invasive ductal carcinomas, 29% (115/390) showed chromosome 17 aneuploidy, mostly associated with grade 3/HER2 2+ (45%) or grade 2/HER2 3+ (55%) that were not amplified. Also, 34% (12/35) of invasive lobular carcinomas showed chromosome 17 aneuploidy; approximately one-third of these cases were HER2 2+ (33%) and HER2 3+ (37%) that were not amplified. Discordance between the results of immunohistochemistry and fluorescence in situ hybridization in both ductal and lobular carcinomas is largely associated with chromosome 17 aneuploidy.     

Does the level of E-cadherin expression correlate with the primary breast carcinoma infiltration pattern and type of systemic metastases?

Relationships between membrane E-cadherin reactivity of invasive carcinoma, a dyshesive growth pattern, and lobular carcinoma-type systemic metastases were studied in 295 breast carcinomas and 57 patients with lobular carcinoma systemic metastases. There were 143 pure lobular carcinomas, 80 mixed (lobular and ductal) carcinomas, and 72 pure ductal carcinomas. Two (7%) of 30 mixed, predominantly lobular carcinomas, 23 (61%) of 38 mixed carcinomas, and 8 (67%) of 12 mixed, predominantly ductal carcinomas had E-cadherin staining in more than 10% of the lobular carcinoma cells. Lobular carcinoma-type systemic metastases were identified in 45 cases (38 [84%], pure lobular; 5 (11%], mixed; 2 [4%], pure ductal). No E-cadherin staining was found in 42 (98%) of 43 lobular carcinomas in cases of lobular carcinoma-type sYstemic metastases and all 57 cases of lobular carcinoma systemic metastases. Absent cell-to-cell adhesion seems to be a necessary property of carcinoma cells to facilitate permeation through tissue planes and produce characteristic lobular carcinoma-type systemic metastases. The level of decreased E-cadherin expression at which a dyshesive growth pattern emerges in primary breast carcinomas may be less than the level associated with lobular carcinoma-type systemic metastases.     

Central atypical papillomas of the breast: a clinicopathological study of 119 cases

The clinicopathological features of central intraductal papillomas of the breast presenting with florid usual ductal hyperplasia or atypical ductal hyperplasia (ADH) were analyzed in a retrospective series of 119 patients, whose lesions were sent to the Armed Forces Institute of Pathology from 1976 to 1990. After histological review considering predefined morphological and quantitative criteria, the 119 central papillomas were classified into 22 papillomas with florid usual ductal hyperplasia (18%), 40 papillomas with focal atypia (34%), 24 atypical papillomas (20%) and 33 carcinomas arising in a papilloma (28%). After a median period of follow-up of 110 months, 16 recurrences (5 papillomas, 2 carcinomas arising in a papilloma, 4 ductal carcinomas in situ, 5 invasive carcinomas) occurred. No statistically significant difference was observed in relation to recurrence for the various categories of papillomas. The presence of epithelial hyperplasia, ADH or lobular neoplasia in the surrounding breast as well as infarction of the papilloma were significant predictive factors of recurrence (P=0.02 and P=0.005, respectively, log-rank test). The main reason for the observed low rate of significant recurrences in this series was that epithelial atypia (whether comprising 20% or 60% of the papillary lesion) was, in most of the cases, localized in a confined lesion that was completely excised.     

CD34+ fibrocytes are preserved in most invasive lobular carcinomas of the breast

It is generally agreed that invasive carcinomas of the breast consistently lack stromal CD34+ fibrocytes. The pertinent literature shows that this assumption is well based for invasive ductal carcinomas, but evidence of loss of stromal CD34+ cells in lobular carcinomas is weak. We present a series of 22 invasive lobular carcinomas (ILCs) which, in contrast to invasive ductal carcinomas, display a gradual reduction of stromal CD34+ fibrocytes. One third of the study population showed a completely preserved population of CD34+ fibrocytes, in another third, this cell population was reduced in comparison to normal breast tissue, and in the remaining third, loss of CD34+ fibrocytes comparable to that occurring in virtually all invasive ductal carcinomas was found. The present study shows that loss of CD34+ fibrocytes is not a consistent feature of invasive carcinomas of the breast. Therefore, a preserved CD34+ stromal cell population does not exclude malignancy, and analysis of the stromal CD34 expression should be handled with care when used as a diagnostic tool.     

Frequent E-cadherin gene inactivation by loss of heterozygosity in pleomorphic lobular carcinoma of the breast.

Pleomorphic lobular carcinoma of the breast is a variant of infiltrating lobular carcinoma that has poor prognosis. The pleomorphic appearance of this variant hinders its correct identification and differentiation from ductal carcinoma. The analysis of E-cadherin glycoprotein expression is a powerful tool for distinguishing lobular from ductal carcinomas, because complete loss of E-cadherin expression occurs in most infiltrating lobular tumors and lobular carcinomas in situ, but not in ductal tumors. In the present study, we have evaluated E-cadherin expression by immunohistochemistry in a series of 29 pleomorphic lobular breast carcinomas, including 7 cases with an in situ component. Complete loss of E-cadherin expression was observed in all the cases (29/29, 100%), in invasive and in situ components. To understand better the mechanisms underlying E-cadherin inactivation in this tumor type, the frequency of loss of heterozygosity at the E-cadherin gene locus (16q22.1) was analyzed. All informative tumors (27/27, 100%) showed loss of heterozygosity, thus implying a strong association between loss of E-cadherin expression and loss of heterozygosity at 16q22.1. Moreover, loss of heterozygosity was detected in all in situ components analyzed. These results imply that in terms of E-cadherin inactivation, pleomorphic lobular tumors are identical to classic infiltrating lobular carcinomas and distinct from ductal tumors, and therefore they should be considered a variant of lobular carcinoma of the breast, despite their aggressive behavior.     

Immunohistochemical detection of antiapoptotic protein X-linked inhibitor of apoptosis in mammary carcinoma

An immunohistochemical survey of X-linked inhibitor of apoptosis (XIAP) expression in mammary carcinoma was performed. XIAP, the most potent of the inhibitor of apoptosis family of caspase inhibitors, has been linked to tumor aggressiveness and therapeutic resistance in several malignancies and is considered an attractive target for cancer drug discovery. Routinely processed sections from 94 ductal carcinomas, 9 lobular carcinomas, and 10 ductal carcinomas with lobular components or features were subjected to citrate-based antigen retrieval, immunostained with anti-XIAP (BD Biosciences, Franklin Lakes, NJ), Envision+ reagents (Dako, Carpinteria, CA), and diaminobenzidine. Positive staining was found in 22.7% of grade 1, 44% of grade 2, and 89.5% of grade 3 ductal carcinomas. Strong staining occurred in no cases of grade 1, 13% of grade 2, and 55.2% of grade 3 ductal carcinomas. XIAP staining increased overall with grade of ductal carcinoma in situ as well. The staining intensity of invasive carcinoma correlated with that of the corresponding ductal carcinoma in situ in 70% of cases. Ductal carcinomas overall showed more staining than lobular carcinomas. XIAP is most strongly and commonly detected in grade 3 ductal carcinoma. The degree of XIAP expression appears frequently to be determined in the preinvasive intraductal phase of tumorigenesis. These findings suggest a possible role of XIAP in the more aggressive clinical behavior of grade 3, compared with lower-grade ductal carcinomas.     

Pathological prognostic factors in breast cancer. IV: Should you be a typer or a grader? A comparative study of two histological prognostic features in operable breast carcinoma

In a study of 1529 patients with primary operable breast carcinoma we have assessed the effect of applying both histological grade and tumour type to determine their comparative value as prognostic factors in human breast cancer. The prognostic group the patient was placed in, based on histological type alone, was less accurate than using grade and type together for many tumours. The importance of performing histological grading of ductal/no special type carcinoma (50% of the women in this series) is confirmed in this series. The 10-year-survival varied from 76% for women with grade 1 carcinoma to 39% for those with grade 3 tumours. Some of the 'special types' of breast carcinoma including tubular, tubulo-lobular, invasive cribriform and grade 1 mucinous carcinomas behaved as would be predicted, with a greater than 80% 10-year-survival in this series. Others, including grade 2 mucinous carcinomas, however, behaved less well with a 60% to 80% 10-year-survival. Indeed, many of the histological tumour types including tubular mixed, ductal/no special type, mixed ductal with special type and lobular carcinomas of classical, solid or mixed types showed a variation in behaviour that could not be predicted by typing alone. Histological grade and tumour type, when used together, more accurately predicted prognosis. In multivariate analysis of a larger group of 2658 cases of primary breast carcinomas (including the 1529 study cases) when histological grade, lymph node status and tumour size were entered, grade was the most important factor in predicting for survival. When histological type of carcinoma was included it was also found to be independently significant, although comparatively of less importance than grade. We conclude that tumours should be typed and graded in order to predict prognosis most accurately and to enable the choice of optimum treatment for women with primary breast carcinoma.     

The role of E-cadherin in low-grade ductal breast tumourigenesis

Grade I invasive ductal breast carcinomas have a specific pattern of genetic aberrations, namely gain of 1q and loss of 16q. This pattern is very similar to the changes seen in invasive lobular breast carcinomas (ILCs). The gene on 16q involved in ILC is known to be E-cadherin (CDH1). This study has investigated whether the same gene is responsible for grade I invasive ductal carcinoma (IDC), using allele imbalance analysis, mutation screening, and immunohistochemistry (IHC). The data suggest that despite the shared pattern of genetic aberrations seen in grade I IDC and ILC, CDH1 is not the target gene in low-grade ductal tumourigenesis.