Nuclear and flow cytometric characteristics associated with overexpression of the c-erbB-2 oncoprotein in breast carcinoma

Ductal carcinoma in situ associated with triple negative invasive breast cancer: evidence for a precursor-product relationship

AIMS

We evaluated pathological features of the ductal carcinoma in situ component of 241 triple negative invasive breast cancers.

RESULTS

We found that 151 (62.6%) in situ lesions were of high nuclear grade, and 236 (97.9%) were triple negative (oestrogen receptor, progesterone receptor, cerbB2 negative). Immunohistochemistry for cytokeratin (CK)5/6, CK14, CK17, epidermal growth factor receptor (EGFR), CD117, 34βE12, p63 and smooth muscle actin (SMA) revealed positive staining in 5 (2.1%), 60 (24.9%), 69 (28.6%), 37 (15.4%), 69 (28.6%), 137 (56.8%), 3 (1.2%) and 22 (9.1%) in situ ductal components respectively, with fair to substantial agreement of staining results (positive versus negative) between in situ and corresponding invasive elements for CK5/6, CK14, CK17, EGFR, CD117 and 34βE12; but none to fair agreement for p63 and SMA respectively. When the tri-panel of CK14, EGFR and 34βE12 was used to define the basal phenotype, 68% revealed basal-like expression of both in situ and invasive components of the same case.

CONCLUSIONS

Our data support the notion that triple negative ductal carcinoma in situ is the precursor of the corresponding invasive counterpart, and that basal-like expression is maintained in the majority of invasive cancers associated with basal-like in situ disease. Future studies that prospectively evaluate morphological and biological characteristics of invasive cancers that develop from triple negative and basal-like ductal carcinoma in situ lesions will assist in validating these findings.

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.

Correlation of nuclear morphometry with pathologic parameters in ductal carcinoma in situ of the breast

Morphometric features of nuclear perimeter, nuclear area, feret ratio, and feret circle were studied in a series of 64 cases of ductal carcinoma in situ (DCIS) of the breast in Singapore women. The results were compared with pathologic parameters of tumor size, nuclear grade, necrosis, cell polarization, and architectural pattern. There was statistically significant correlation between nuclear perimeter and area with all the pathologic parameters, with the strongest association observed for nuclear grade (P <.0001). Higher grade nuclei as assessed histologically were associated with larger nuclear area (44.14 microm(2) in low-grade lesions, 47.77 microm(2) in intermediate-grade lesions, and 72.05 microm(2) in high-grade lesions) and perimeter (25.94 microm in low-grade nuclei, 27.12 microm in intermediate-grade nuclei, and 33.66 microm in high-grade nuclei). DCIS lesions with necrosis and absence of polarization also revealed increased nuclear area and perimeter (P <.05). Comedo architecture was associated with larger nuclear area and perimeter (65.97 microm(2), 31.7 microm) than the papillary subtype (42.17 microm(2), 25.29 microm), with the mixed morphologic pattern disclosing intermediate values (54.83 microm(2), 29.43 microm). There was direct correlation for tumor size with nuclear area and perimeter (P <.01). No similar relationship was found between pathologic parameters and feret ratio or circle, indicating that nuclear roundness or lack of it did not factor as a significant component in the pathologic assessment.

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.

Comparison of pathological and biological features of symptomatic and mammographically detected ductal carcinoma in situ of the breast

To determine whether the ductal carcinoma in situ (DCIS) detected mammographically or presenting clinically is the same or differs, pathological and biological (c-erbB-2 and p53 detection) features of 79 cases of pure DCIS, 5 cases with microinvasion and 8 cases with 1 to 2 mm of invasion, all detected by mammography, have been compared with 59 cases of pure DCIS, 8 cases with microinvasion and 7 cases with 1 to 2 mm invasion, all of which presented clinically. Half of the mammographically detected group were smaller than 20 mm, and there was a higher incidence of these being low grade, whereas 30% of the symptomatic cases were smaller than 20 mm, and more of this group were larger than 50 mm. For the pure DCIS, there were less high-grade and more intermediate-grade cases in the mammographically detected group, although the incidence of low grade was similar between the two groups. There were more cases with a micropapillary pattern in the symptomatic group. C-erbB-2 protein was detected in 42% of the mammographically detected cases, whereas 59% of the symptomatic cases had c-erbB-2 reactivity. P53 detection was similar for both groups (33.0% and 37.0%). There were more symptomatic cases with invasion, and these were predominantly high grade, whereas the mammographically detected cases were both high and intermediate grade. Twelve of the 15 symptomatic cases with invasion expressed c-erbB-2, in comparison with 4 of the 13 mammographically detected cases, with half of the high-grade lesions in the latter group being negative. This study has shown that although there is overlap of pathological and biological features between DCIS presenting clinically and that detected mammographically, there can be differences in extent, grade, and invasion. The impact of this, however, can be determined only by clinical follow-up.

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.

ERBB2 oncogene in human breast cancer and its clinical significance

We reveiwed the relationships between ERBB2 amplification and/or overexpression in human breast cancer and the clinicopathological parameters described in the literature (97 studies involving 22,616 patients) in order to draw conclusions regarding its clinical interest. The mean of ERBB2 positivity (26%, ranging from 5 to 55%) is not dependent on the method used to evaluate ERBB2 amplification or overexpression. Despite the discrepancies observed between the different studies, several associations between ERBB2 positivity and the classical clinicopathological parameters were noted. There are clear relationships between ERBB2 positivity and the lack of steroid receptors, the histological subtypes of mammary tumours (ductal invasive and in situ), worse histological and nuclear grades, aneuploidy and high rate of proliferation. In univariate analyses, ERBB2 is strongly associated with poor prognosis. All these data indicate that ERBB2 is a marker of aggressiveness of the tumour. However, ERBB2 does not retain a clinical prognostic significance in multivariate analyses, since it is associated with several strong prognostic parameters. When considering the prognostic value of ERBB2 in relation to treatment, a significantly worse survival of the treated patients is noted in ERBB2 positive patients. This suggest that ERBB2 could be a marker of reduced response to chemotherapy and hormonal treatment. With respect to the tumour response to treatment, the results, provided as yet by pilot studies, remain controversial and further investigations are necessary to evaluate the predictive value of ERBB2. Finally, new therapeutic approaches targeting the cells overexpressing ERBB2 have been developed.

c-erbB-2/neu protein expression, DNA ploidy and S phase in breast cancer

DNA content and c-erbB2/neu protein (p185) expression were evaluated by flow-cytometry and ELISA, respectively, in 166 specimens of primary breast cancer. A non-diploid DNA content was found in 88 tumours (53%), with the DNA index ranging from 0.7-2.7. S phase fraction (SPF) evaluation, performed in 130 cases, showed significantly higher values in aneuploid than in diploid tumours (median values, 17.3% and 5.8%, respectively). Thirty-six tumours (21.6%) showed p185 overexpression, while 45 (27.1%) and 85 (51.3%) showed intermediate and low expression, respectively. A good correlation (P = 0.0023) was found between DNA content and p185 positivity. Tumours with high p185 values were mainly aneuploid, while tumours with intermediate or low expression had variable degrees of DNA content. Furthermore, p185 concentration was significantly higher in aneuploid than in diploid tumours (P = 0.009). The highest rate of p185 (+) cases and the highest p185 concentrations occurred in triploid (1.3 < D.I. < or = 1.7), compared to the other tumours. SPF values and p185 positivity rates were not significantly correlated in diploid and in aneuploid tumours.

Soluble c-erbB-2 fragment in serum correlates with disease stage and predicts for shortened survival in patients with early-stage and advanced breast cancer

Seventy-nine patients with advanced breast cancer were tested for the presence, in serum, of a 110 kDa soluble, c-erbB-2 fragment. Thirty-nine patients were seropositive. There was no correlation between seropositivity and menopausal status, or with oestrogen status. In addition, no correlation could be found between tissue c-erbB-2 immunostaining for the external domain of the c-erbB-2 receptor and the presence of soluble c-erbB-2 in serum. The presence of serum soluble c-erbB-2, however, had a significant impact on survival of patients with advanced disease, suggesting that this test may become a useful independent prognostic indicator.

Simultaneous analysis of c-erbB-2 expression and DNA content in breast cancer using flow cytometry

The c-erbB-2 oncogene is frequently amplified and overexpressed in human breast cancer. We have studied the c-erbB-2 protein in conjunction with DNA content in frozen samples from breast cancers using flow cytometry. The cell suspensions were obtained by mechanical disaggregation followed by a short fixation in 1% paraformaldehyde. The level of c-erbB-2 expression was calculated as a fluorescence index, taking into account the relative amount of total cellular fluorescence compared to nonspecific fluorescence. The flow cytometric value correlated with immunohistochemical results obtained with the same monoclonal antibody (c-neu, clone 9G6). Overexpression of c-erbB-2 was significantly more frequent in DNA aneuploid tumors than in DNA diploid ones and correlated with increasing S-phase fraction and estrogen receptor negativity. In 10 DNA multiploid tumors, the different aneuploid stemlines uniformly expressed c-erbB-2, supporting the hypothesis that overexpression is an early event in breast cancer. Of the 172 tumors, the 37 (22%) judged as positive with immunohistochemistry showed a somewhat higher rate of distant recurrence than others (P = 0.14). The fluorescence index was significantly associated with prognosis (P = 0.0012), as it was also among the immunohistochemically positive cases. If the degree of overexpression is important, then flow cytometry could be a feasible technique for classification.

What's new in breast cancer? Molecular perspectives of cancer development and the role of the oncogene c-erbB-2 in prognosis and disease

The oncogene c-erbB-2 is frequently amplified in human breast carcinoma. The c-erbB-2 gene is present as a single copy in normal cells, and has been mapped to chromosome 17 in the region 17q 12-21.32. c-erbB-2 encodes a transmembrane glycoprotein known as p185. The intracellular component of p185 has tyrosine kinase activity; the extracellular domain has a structure resembling a growth factor receptor. c-erbB-2 amplification, p185 overexpression and levels of transcribed c-erbB-2 specific messenger RNA have been studied in a large number of breast carcinomas using a variety of techniques. In general, overexpression of p185 oncoprotein reflects various levels of DNA amplification, though in some cases amplification can be detected in the absence of overexpression of p185 and similarly overexpression of p185 can be present without detectable levels of c-erbB-2 amplification. This findings suggests that multiple mechanisms may be responsible for overexpression. c-erbB-2 amplification and/or overexpression occurs in almost all cases of high grade duct carcinoma in-situ, but has been reported in only 10%-40% of infiltrating duct carcinoma. c-erbB-2 amplification or overexpression occurs rarely in invasive lobular carcinoma, and has not been detected in ductal or lobular epithelial hyperplasia, or in atypical ductal or atypical lobular hyperplasia. It is generally believed that c-erbB-2 amplification/overexpression is an important independent prognostic indicator in breast carcinoma, identifying a subset of patients with poor prognosis tumours, particularly if axillary node metasases are present. However, many unanswered questions remain regarding c-erbB-2 and its role in breast cancer development and progression. The causes of c-erbB-2 amplification are unknown. There is no evidence of mutations in the human gene which might cause amplification or overexpression. The significance of the differences in levels of c-erbB-2 amplification/overexpression in in-situ duct carcinoma and associated invasive duct carcinoma has not been established. Amplification or overexpression have not been reported in atypical duct hyperplasia, a proposed precursor of duct carcinoma in-situ, yet overexpression occurs almost always in high grade duct carcinoma in-situ. c-erbB-2 may play a critical role in the development of a clonal in-situ, proliferation of high histological grade, yet does not obviously influence the acquisition of an invasive phenotype. We would postulated that this instability in amplification/overexpression is of biological significance, and if better understood may aid in the study of progression of human breast carcinoma.

Immunohistochemical overexpression of C-erbB-2 in the prognosis of breast cancer

Immunohistochemical c-erbB-2 protein overexpression was detected in 34 of 124 (27.4%) paraffin-embedded breast cancer specimens. Although no difference was seen between the c-erbB-2 positive and negative groups in 5-year disease-free survival, 5-year overall survival was significantly less favorable in the c-erbB-2 positive group. Furthermore, patients graded as having positive c-erbB-2 staining and aneuploid DNA showed significantly poorer survival than those in other categories. The significant prognostic factors, determined by a multivariate analysis, were nodal status and c-erbB-2 overexpression. Our findings therefore suggest that c-erbB-2 expression is a prognostic factor in breast cancer and that it could be useful in the determination of postoperative adjuvant therapy.

p53 protein expression in mammary ductal carcinoma in situ: relationship to immunohistochemical expression of estrogen receptor and c-erbB-2 protein

The immunohistochemical expression of the p53 gene protein was examined in a consecutive series of 143 cases of pure ductal carcinoma in situ (DCIS) of the breast. Expression of wild-type and/or mutant p53 protein was detected in 36 (25.2%) of the cases examined, as evidenced by positive nuclear staining with the monoclonal antibody DO 7. Thirty-four (35.8%) of the large cell cases showed p53 protein expression compared with two (4.1%) of the small cell cases (chi 2 = 15.3 [df = 1], P < .001). p53 Protein expression also was associated with an increased histologic degree of necrosis, with a nearly significant association of negative tumor estrogen receptor status and p53 protein expression. No significant association of p53 protein expression and c-erbB-2 protein expression was seen. Immunohistochemical expression of p53 protein is present in approximately 25% of DCIS cases and is confined almost exclusively to large cell DCIS, a morphologic subtype of in situ breast carcinoma thought to be more biologically aggressive. Expression of p53 protein may be important in the neoplastic progression of DCIS, reflecting the acquisition of p53 gene mutations in large cell DCIS cases. Therefore, p53 may be implicated in mammary tumor evolution from in situ to invasive disease.