Borgny Ytterhus

Detection and Quantitation of HER-2 Gene Amplification and Protein Expression in Breast Carcinoma

We compared fluorescence in situ hybridization (FISH), immunohistochemical analysis, immunocytochemical analysis, and relative quantification assays using polymerase chain reaction (PCR) as methods for estimating HER-2 gene amplification and protein overexpression infine-needle aspirate (FNA) specimens and paraffin-embedded tissue samples from 49 cases of breast cancer: FISH can be performed successfully on FNA smears. Immunohistochemical and immunocytochemical staining intensity of 3+ corresponds to a FISH ratio of more than 2.5. Immunohistochemical and immunocytochemical staining of 2+ and 1+ are not necessarily associated with gene amplification. Increased DNA PCR ratios might be seen without amplification, reflecting polysomy. HER-2 messenger RNA relative quantitation scores correlate well with HER-2 gene amplification. Owing to the ease with which it can be performed and interpreted, we conclude that FISH is the test of choice for HER-2 estimation and, when possible, should be performed on whole nuclei, which are readily available in FNA smears or imprint cytology. FISH may be used primarily or to confirm immunohistochemical, immunocytochemical, and PCR results.

Overexpression of c-erbB2 is a negative prognostic factor in anaplastic astrocytomas

The epidermal growth factor receptor (EGFR) family, consisting of four tyrosine kinase receptors, c-erb B1-4, seems to be influential in gliomagenesis. The aim of this study was to investigate EGFR gene amplification and expression of c-erb B1-4 receptor proteins in human anaplastic astrocytomas. Formalin-fixed and paraffin-embedded sections from 31 cases were investigated by standard immunohistochemical procedures for expression of c-erb B1-4 receptor proteins using commercial antibodies. EGFR gene amplification was studied by fluorescence in situ hybridization using paraffin-embedded tissues. Two monoclonal antibodies, NCL-EGFR-384 and NCL-EGFR, were used for EGFR detection and they displayed positive immunoreactivity in 97% and 71%, respectively. For c-erb B2 detection three monoclonal antibodies, CB11, 3B5, and 5A2, were applied and they displayed positive immunoreactivity in 45%, 100%, and 52%, respectively. Positive immunostaining for c-erb B3 and c-erb B4 was encountered in 97% and 74%, respectively. The EGFR gene was amplified in 9 out of 31 tumors (29%). After adjusting for age, Karnofsky performance status, and extent of surgical resection, Cox multiple regression analysis with overall survival as the dependent variable revealed that c-erb B2 overexpression detected by the monoclonal antibody clone CB11 was a statistically significant poor prognostic factor (P = 0.004). This study shows the convenience and feasibility of immunohistochemistry when determining the expression of receptor proteins in tissue sections of human astrocytomas. The synchronous overexpression of c-erb B1-4 proteins in anaplastic astrocytomas supports their role in the pathogenesis of these tumors. Further, c-erb B2 overexpression seems to predict aggressive behaviour.

Abnormal chromosome 8 copy number in cytological smears from breast carcinomas detected by means of fluorescence in situ hybridization (FISH)

Numerical change in chromosome 8 is an acquired abnormality associated with high clinical stage and may be involved in the conversion of carcinoma in situ in the breast to invasive carcinoma. Fine needle aspiration smears from 53 cases of breast carcinoma were hybridized with centromeric probes for chromosome 8 and the X chromosome. Thirty‐eight cases revealed chromosome 8 copy gain. Of the 45 grade II and III tumours, 28 showed polysomy (>3 signals) and six showed trisomy. Of the eight grade I tumours, four were trisomic, none were polysomic. There were only two cases of chromosome 8 copy loss (one each of grade I and III). X chromosome polysomy was also a frequent finding although the signal counts were similar to those for chromosome 8 in only a few cases. Chromosome 8 polysomy occurs frequently in breast carcinoma and high copy number (>3) is associated with high malignancy grade.

TOP2A gene copy number change in breast cancer.

Aims The clinical significance of TOP2A as a prognostic marker has not been clarified. The aims of this study were to investigate the frequency of TOP2A copy number change; to correlate TOP2A with HER2 status, hormone receptor (HR) status and molecular subtype, and further to explore differences in breast cancer-specific survival according to TOP2A and HER2. Methods In this study, TOP2A, HER2 and chromosome 17 copy number were assessed in 670 cases of breast cancer using in situ hybridisation techniques. Gene to chromosome ratios ≥2 were classified as amplification. TOP2A deletion (gene to chromosome ratio ≤0.8) or monosomy (only one signal for both gene and chromosome in more than 75% of nuclei) were classified as gene loss. Results A strong association between TOP2A change and HR and HER2 status was found. During the first 5 years after diagnosis, the risk of death from breast cancer was significantly higher for cases with HER2 amplification irrespective of TOP2A status. Conclusions TOP2A copy number change was strongly associated with HR and HER2 status and as a prognostic marker TOP2A is probably of limited value.

Detection of Trisomy 18 on Formalin-fixed and Paraffin-embedded Material by Fluorescence In Situ Hybridization

Formalin-fixed and paraffin-embedded autopsy material from 10 fetuses and infants with unknown karyotype and anomalies suggestive of trisomy 18 were subjected to fluorescence in situ hybridization (FISH). Nuclei were extracted from the tissues and hybridized with a chromosome 18–specific centromere probe. The hybridization was successful in 9 of 10 cases. Two cases showed three hybridization signals in most of the nuclei (74% and 85%). These had anomalies frequently occurring with trisomy 18 (congenital heart defect, omphalocele, and horseshoe kidney). Two cases showed a mixture of two and three signals (47%/49% and 59%/36%), suggesting the possibility of mosaicism. One of these cases had anomalies consistent with a trisomy 18 phenotype. In the other case intrauterine growth retardation and syndactylies suggested triploidy. Hybridization with a chromosome 8–specific probe gave a distribution of two and three signals (34% and 62%, respectively). This result strengthened the suspicion of a possible triploid mosaicism. In five of the cases most of the nuclei showed two signals (85% to 88%). However, as only one type of tissue was examined for enumeration of chromosome 18, the possibility of organ mosaicism or other chromosome aberrations cannot be excluded. The FISH technique is applicable on macerated and autolysed formalin-fixed tissue, making it possible to retrospectively analyze autopsy material from aborted and stillborn fetuses and infants. This analysis contributes to a better quality of perinatal autopsies and is helpful in parental counseling.

Molecular Subtypes of Breast Cancer: Long-term Incidence Trends and Prognostic Differences

Background: Secular trends in incidence and prognosis of molecular breast cancer subtypes are poorly described. We studied long-term trends in a population of Norwegian women born 1886–1977. Methods: A total of 52,949 women were followed for breast cancer incidence, and 1,423 tumors were reclassified into molecular subtypes using IHC and in situ hybridization. We compared incidence rates among women born 1886–1928 and 1929–1977, estimated age-specific incidence rate ratios (IRR), and performed multiple imputations to account for unknown subtype. Prognosis was compared for women diagnosed before 1995 and in 1995 or later, estimating cumulative risk of death and HRs. Results: Between 50 and 69 years of age, incidence rates of Luminal A and Luminal B (HER2−) were higher among women born in 1929 or later, compared with before 1929 [IRRs 50–54 years; after imputations: 3.5; 95% confidence interval (CI), 1.8–6.9 and 2.5; 95% CI, 1.2–5.2, respectively], with no clear differences for other subtypes. Rates of death were lower in women diagnosed in 1995 or later, compared to before 1995, for Luminal A (HR 0.4; 95% CI, 0.3–0.5), Luminal B (HER2−; HR 0.5; 95% CI, 0.3–0.7), and Basal phenotype (HR 0.4; 95% CI, 0.2–0.9). Conclusions: We found a strong secular incidence increase restricted to Luminal A and Luminal B (HER2−) subtypes, combined with a markedly improved prognosis for these subtypes and for the Basal phenotype. Impact: This study documents a clear secular increase in incidence and a concomitant improved prognosis for specific molecular breast cancer subtypes. Cancer Epidemiol Biomarkers Prev; 25(12); 1625–34. ©2016 AACR.

Amplification of TOP2A and HER-2 genes in breast cancers occurring in patients harbouring BRCA1 germline mutations.

BRCA1 associated tumours are found to express an oestrogen receptor negative “basal epithelial-like” phenotype. In contrast to ER negative tumours in general, such tumours rarely harbour amplification of the HER-2 gene. However, little is known about TOP2A gene amplification status in BRCA1-associated tumours. Such information may be of importance to therapy, as amplification of TOP2A has been associated with dose-dependent sensitivity to anthracycline therapy in breast cancer. We examined 40 breast carcinomas from BRCA1 mutation carriers and 40 sporadic breast carcinomas matched for age, tumour diameter and histological grade for HER-2 and TOP2A amplification status using fluorescence in situ hybridisation (FISH). Co-amplification of TOP2A and HER-2 was found in four of the mutation carriers and in three of the controls. While six tumours in the control group harboured HER-2 amplifications with normal TOP2A, this occurred in three of the BRCA1 associated tumours only. In contrast, three of the BRCA1-associated tumours but none of the controls harboured TOP2A amplification despite normal HER-2 status. Our findings have potential therapeutic implications. HER-2 assessment is routinely used to select breast cancer patients for trastuzumab but also dose-intensive anthracycline therapy. Our data suggest that BRCA1-associated breast cancers also need to be tested for TOP2A amplification.

Expression and clinical value of EGFR in human meningiomas

Background Meningiomas are common intracranial tumors in humans that frequently recur despite having a predominantly benign nature. Even though these tumors have been shown to commonly express EGFR/c-erbB1 (epidermal growth factor receptor), results from previous studies are uncertain regarding the expression of either intracellular or extracellular domains, cellular localization, activation state, relations to malignancy grade, and prognosis. Aims This study was designed to investigate the expression of the intracellular and extracellular domains of EGFR and of the activated receptor as well as its ligands EGF and TGFα in a large series of meningiomas with long follow-up data, and investigate if there exists an association between antibody expression and clinical and histological data. Methods A series of 186 meningiomas consecutively operated within a 10-year period was included. Tissue microarrays were constructed and immunohistochemically analyzed with antibodies targeting intracellular and extracellular domains of EGFR, phosphorylated receptor, and EGF and TGFα. Expression levels were recorded as a staining index (SI). Results Positive immunoreactivity was observed for all antibodies in most cases. There was in general high SIs for the intracellular domain of EGFR, phosphorylated EGFR, EGF, and TGFα but lower for the extracellular domain. Normal meninges were negative for all antibodies. Higher SIs for the phosphorylated EGFR were observed in grade II tumors compared with grade I (p = 0.018). Survival or recurrence was significantly decreased in the time to recurrence analysis (TTR) with high SI-scores of the extracellular domain in a univariable survival analysis (HR 1.152, CI (1.036–1.280, p = 0.009)). This was not significant in a multivariable analysis. Expression of the other antigens did not affect survival. Conclusion EGFR is overexpressed and in an activated state in human meningiomas. High levels of ligands also support this growth factor receptor system to be involved in meningioma tumorigenesis. EGFR may be a potential candidate for targeted therapy.

Characterization of FGD5 Expression in Primary Breast Cancers and Lymph Node Metastases

Faciogenital dysplasia 5 (FGD5) amplification drives tumor cell proliferation, and is present in 9.5% of breast cancers. We describe FGD5 expression, assess associations between FGD5 amplification and FGD5 expression, and assess FGD5 expression in relation to proliferation and prognosis. FGD5 immunohistochemistry was done on primary tumors (n=829) and lymph node metastases (n=231) from a cohort of Norwegian patients. We explored associations between FGD5 amplification, FGD5 expression, and proliferation, and analyzed the prognostic value of FGD5 expression by estimating cumulative risks of death and hazard ratios (HRs). We identified nuclear and cytoplasmic expression in 64% and 73% of primary tumors, respectively, and found an association between gene amplification and nuclear expression (p=0.02). The proportion of cases with FGD5 expression was higher in lymph node metastases, compared with primary tumors (p=0.004 for nuclear and p=0.001 for cytoplasmic staining). Neither proliferation nor prognosis was associated with FGD5 expression (age-adjusted HR 1.12 [95% confidence interval = 0.89–1.41] for nuclear expression; and 0.88 [95% CI = 0.70–1.12] for cytoplasmic expression). FGD5 is expressed in a high proportion of breast cancers and lymph node metastases. There was a correlation between FGD5 amplification and nuclear expression, but no association between FGD5 expression and proliferation or prognosis.