Daniel W. Visscher

Determination of Her-2/Neu status in breast carcinoma: comparative analysis of immunohistochemistry and fluorescent in situ hybridization.

Her-2/neu (H2N) status in breast carcinoma has been considered a prognostic factor that may have therapeutic implications; however, the correlation between H2N overexpression and gene amplification has not been completely defined. A consecutive series of ductal carcinomas (34 invasive and 7 in situ) were analyzed by fluorescent in situ hybridization for H2N gene and chromosome 17 copy number using touch preps of intact cells and by immunohistochemistry, using three different commercial antibodies to H2N protein (Zymed, clone 31G7; Ventana, clone CB11; and Dako, polyclonal) in corresponding formalin-fixed, paraffin-embedded tissue sections. Gene amplification was classified as unequivocal if more than five signals were present in more than 80% of the counted nuclei and absent if more than 80% of the nuclei counted contained two or fewer gene copies. Cases that did not fulfill the above criteria were considered equivocal for amplification. Immunostaining was classified as follows: 0 = no staining; 1+ = faint, incomplete membranous pattern; 2+ = moderate, complete membranous pattern; 3+ = strong membranous pattern. Of the 34 invasive tumors, 10 (29%) had unequivocal gene amplification. Furthermore, all had more than 10 copies of the gene in more than 60% of the counted nuclei. An additional nine cases (26%) had equivocal amplification, which was usually the result of chromosome 17 aneuploidy (seven of nine) or heterogeneity. With the Zymed and Dako antibodies, all tumors with 3+ staining had unequivocal gene amplification and all cases with 2+, 1+, or 0 staining were negative or equivocal for gene amplification. With the Ventana antibody, all cases with 3+ staining had unequivocal gene amplification, but two cases with unequivocal amplification by fluorescent in situ hybridization exhibited 1+ staining. Moderate (2+) H2N staining was observed in one case, three cases, and five cases with the Ventana, Dako, and Zymed reagents, respectively, and did not correlate with H2N gene copy number. Discordance between H2N and chromosome 17 copy number was not a useful means of defining amplification. Two cases of ductal carcinoma in situ with the Zymed antibody and two with the Dako antibody showed 3+ staining despite lack of unequivocal gene amplification. We conclude that (1) strong H2N immunostaining is highly associated with gene amplification, although there is minor variation in sensitivity between different antibodies; (2) a subset of breast carcinomas (3 to 15%) demonstrate moderate H2N staining without evidence of amplification, and it is unclear whether they represent highly sensitive staining or are a subset of cases that show overexpression without amplification; (3) gene amplification, as detected by fluorescent in situ hybridization, is associated with at least 10 gene copies per nucleus, and lower gene copy duplication (3 to 4/nucleus) is frequent, usually the result of chromosome 17 polysomy, and not associated with high-level overexpression; (5) overexpression of H2N without amplification may be more frequent in ductal carcinoma in situ, implying a different role in the biology of preinvasive versus invasive neoplasm.

Clinicopathologic analysis of invasive micropapillary differentiation in breast carcinoma

Invasive micropapillary carcinoma (IMPCa) of breast is histologically characterized by growth of cohesive tumor cell clusters within prominent clear spaces resembling dilated angiolymphatic vessels. In this study, eighty three breast carcinomas with IMPCa differentiation were identified by review of the invasive carcinoma cases in our institution and correlated retrospectively with standard clinicopathologic parameters and survival status relative to a control series of cases (mean follow up 7 years). IMPCa growth pattern was present in 6% of all breast carcinomas; it was generally a focal component in otherwise typical invasive ductal carcinoma. It comprised more than 80% of the total neoplasm in only 10 cases (12%), 50–80% of the neoplasm in 7 cases (8%), 20–50% of the neoplasm in 22 cases (26%) and less than 20% in 44 cases (53%). The mean tumor size was 4 cm, 22% invaded skin, and 58% were poorly differentiated, but 71% were ER positive. Axillary node metastases were present in 77% of cases, were typically multiple (51% had three or more positive), and usually contained an IMPCa component (81% of the cases). There was no significant difference in node status, ER status, size, tumor grade, or peritumoral angiolymphatic invasion between tumors with predominant (more than 50%) v/s focal IMPCa components. In both groups 46% of the patients died from their disease (mean interval to death = 36m). Skin involvement and nodal status were the only parameters which predicted poor survival (P =.01). The outcome of patients with IMPCa did not differ significantly from infiltrating ductal carcinomas of similar node status. In conclusion, our results suggest that IMPCa growth pattern may be a manifestation of aggressive behavior, as shown by frequent skin invasion and extensive nodal involvement. However, clinicopathologic features and outcome of IMPCa are not strongly dependent on the relative amount of micropapillary component.

Centrally necrotizing carcinomas of the breast: a distinct histologic subtype with aggressive clinical behavior.

Most breast carcinomas exhibit ductal differentiation. However, recognition of less common histologic patterns provides clinically useful data. This report describes a distinctive subtype of breast carcinoma that we have termed “centrally necrotizing carcinoma” (CNC; in this study, N = 34), which is characterized by an unusual and aggressive natural history. Centrally necrotizing carcinomas are composed of well-circumscribed, unicentric nodules with extensive central necrosis that are surrounded by a narrow rim of viable high-grade tumor cells. These tumor cells show minimal ductal differentiation (i.e., tubule formation), but are usually associated with focal ductal carcinoma in situ. The mean age of the patients in this study was 57.5 ± 11.6 years, and the mean tumor size was 2.5 ± 1.2 cm. Twenty-eight percent of the patients had positive axillary lymph nodes (mean number of lymph nodes involved, 2.1 ± 1.2). Ninety-four percent of cases were negative for estrogen and progesterone receptors. In 21 patients (62%), local and/or distant recurrences developed (median time to recurrence, 16.2 months), and, to date, 20 have died from breast cancer (median time to death, 22.5 months). Progression of disease (defined as the development of either a recurrence or death resulting from disease) occurred in 24 patients (71%). Comparison with a set of 26 poorly differentiated ductal carcinomas with (nonextensive, patchy) necrosis matched for age, tumor size, and lymph node status showed a significantly worse progression-free survival rate for the CNC group (p <0.004). We conclude that CNC is an uncommon but readily identifiable subtype of breast carcinoma and is characterized by early systemic metastasis and an accelerated clinical course.

Evaluation of MYC and chromosome 8 copy number in breast carcinoma by interphase cytogenetics.

We used fluorescence in situ hybridization (FISH) to determine MYC and chromosome 8 copy number on whole nuclear imprint preparations of 24 breast carcinomas, seven benign breast samples, and two phyllodes tumors. None of the benign tissues and neither of the phyllodes tumors demonstrated an increased copy number for MYC or chromosome 8, which was defined as greater than two signals in > 10% of nuclei. In contrast, 22 of 24 carcinomas demonstrated an increased MYC copy number. The modal numbers of MYC copies/nucleus were 0–2 in seven cases (29%), 3–5 in seven cases (29%), 6–9 in five cases (21%), and >9 in five cases (21%). An increased chromosome 8 copy number was observed in 21 of 22 carcinomas with MYC gain, and the modal number of signals/nucleus was either identical to (n = 14; 64%) or less than (n = 8; 36%) the number of MYC copies. The number of MYC copies correlated with cellular DNA content, as determined by using flow cytometry. In peridiploid tumors (DNA index 0.9–1.2; n = 7), the MYC copy numbers/nucleus were 0–2 in five cases and 3–5 in two cases. In contrast, the modal MYC copy numbers/nucleus among the 11 hyperdiploid tumors (DNA index 1.3–1.9) were 0–2 in one case, 3–5 in four cases, 6–9 in five cases, and >9 in one case. All three tetraploid/hypertetraploid carcinomas exhibited >9 MYC copies/nucleus. We conclude that an increased MYC copy number, as detected by using interphase cytogenetics, is extremely frequent in human breast carcinomas. However, in most cases, MYC gene duplication is probably secondary to polysomy of chromosome 8 and/or genomic endoreduplication (i.e., DNA aneuploidy). Genes Chromosom. Cancer 18:1–7, 1997.

Interaction of transforming growth factor-alpha and epidermal growth factor receptor in breast carcinoma. An immunohistologic study.

Background. Interaction of transforming growth factor‐alpha (TGF‐α) with its receptor, epidermal growth factor receptor (EGFR), has been implicated as an autoregulatory autocrine mechanism of breast epithelial proliferation.

CLINICOPATHOLOGIC ANALYSIS OF MACROPHAGE INFILTRATES IN BREAST CARCINOMA

We compared macrophage density, assessed by enumeration of peritumoral mononuclear cell immunoreactivity for HAM 56, to clinicopathologic features and to immunostaining for two invasion-associated proteases (Cathepsin D and Urokinase plasminogen activator) in 80 breast carcinomas. Diffuse (2+) infiltrates of HAM 56- positive mononuclear cells were present in 27 cases (34%) and 43 (54%) exhibited focal (1+) infiltrates. Presence of 2+ macrophage infiltrates correlated significantly with poor differentiation. None of the seven well-differentiated cases exhibited 2+ infiltrates, whereas 9/43 (21%) moderately differentiated and 18/30 (60%) poorly differentiated tumors were diffusely infiltrated (p = .001). Wide-spread macrophage infiltrates were also more frequent in cases with advanced stage (23% of node negative vs 40% of node positive cases, p = NS). Forty-four percent of the cases with diffuse macrophage infiltrates were cathepsin D positive (i.e. in host derived cells) vs only 18% with focal macrophage infiltrates (p = .002). A similar relationship was observed between staining for HAM 56 and urokinase-type plasminogen activator (p = .02). Disease recurrences (50 months median follow-up) were more frequent in patients with 2+ (17/27, 63%) as opposed to 0+ (1/10, 10%) macrophage infiltrates (p = .01). We conclude that the density of stromal macrophage infiltrates is associated with clinical aggressiveness in breast carcinomas. Further, this relationship may reflect contribution of host derived macrophages to invasion and metastasis through elaboration of proteases which putatively mediate degradation and remodeling of extracellular matrix.

Evaluation of chromosome 12 copy number in ovarian granulosa cell tumors using interphase cytogenetics.

Trisomy 12 is frequently observed in karyotypes of ovarian sex cord-stromal tumors, including adult and juvenile granulosa cell tumors (AGCTs and JGCTs). We assessed the ability to detect this abnormality in deparaffinized tissue sections of 19 ovarian GCTs (17 AGCTs, two JGCTs) and in one fibrothecoma by simultaneous in situ hybridization with fluorescent-labeled centromeric probes to chromosomes 12 (fluorescein isothiocyanate conjugated) and 17 (rhodamine conjugated). In order to quantitate the artifact introduced by nuclear slicing, such analyses were performed both on intact tissue sections and on cytospins of nuclei prepared by enzymatic dissociation from the corresponding tissue block. The series was also evaluated for numerical abnormalities of chromosome X, a less common cytogenetic finding in GCT. Twelve of 19 cases (63%) displayed evidence of trisomy 12 (defined as signal gain in > or = 10% of nuclei) in the intact section, the cytospin, or both. Trisomy for chromosome 17 was present in one case, and trisomy X was present in two cases. In tissue sections the incidence of signal gain for the chromosome 12 probe varied from 0-45% of nuclei (mean 19%). In cytospin preparations, the percentage signal gain for chromosome 12 ranged from 0 to 84% (mean 33%). This study supports the presence of trisomy 12 as a common, but not defining, cytogenetic anomaly in ovarian GCTs. Its presence, however, within only a minority of tumor cells may be partly explained by slicing artifact associated with intact tissue sections, although partial involvement of intact nuclei suggests that trisomy 12 may also be encountered as a heterogeneous abnormality within neoplastic populations of GCTs.

Clinicopathologic Analysis of k-ras, p53, and ERBB-2 Gene Alterations in Pulmonary Adenocarcinoma

We compared PCR-SSCP detected mutations of k-ras (codon 12) and p53 (exons 5-8) to ERBB-2 immunostaining and clinicopathologic features in 31 pulmonary adenocarcinomas. There were nine tumors (29%) with mutations of ras, 13 tumors (42%) with mutations of p53, and three tumors (10%) with mutations of both. Neither k-ras nor p53 mutation alone was significantly correlated with stage, grade, or survival. However, tumors with k-ras mutation were more frequently associated with an invasive growth pattern, defined as > 30% tumor volume composed of infiltrative nests of cells within desmoplastic, scar-like stroma [< 30% volume invasive--1/13 (8%) with k-ras mutation vs. > 30% volume invasive--8/18 (44%) with k-ras mutation, p = 0.02]. Accordingly, k-ras mutations were observed in only 1/9 (15%) predominantly bronchoalveolar or papillary tumors versus 6/22 (28%) acinar or scar carcinoma tumors. All three patients with combined k-ras/p53 mutation had advanced stage (III/IV) at presentation and died of the disease. In contrast to k-ras, staining for ERBB-2 was more frequently observed in tumors exhibiting < 30% invasive growth pattern (12/13, 92%) than in tumors with > 30% invasive growth pattern (10/18, 56%, p = 0.03). ERBB-2 immunoreactivity was more frequent in Stage I (14/15, 93%) versus Stage II-IV (8/16, 50%) cases, but it did not correlate with survival. There was a reciprocal relationship between k-ras mutation and ERBB-2 staining; only 4/9 (44%) k-ras mutated cases were ERBB-2 positive versus 18/22 (82%) cases without k-ras mutation (p = 0.005). In contrast, 8/13 cases with p53 mutation were ERBB-2 positive. We conclude that well-differentiated and less invasive papillary and bronchoalveolar tumors are more often ERBB-2 positive/k-ras negative (i.e. at codon 12), whereas less well differentiated acinar or scar carcinomas are more often ERBB-2 negative/k-ras mutated at codon 12. These findings imply that the divergent histogenesis of pulmonary adenocarcinoma may reflect specific differences in genetic pathology.

IMMUNOHISTOLOGIC ANALYSIS OF INVASIVE PHENOTYPE IN BREAST CARCINOMA : A CLINICOPATHOLOGIC STUDY

Acetone-fixed, cryostat sections of 81 snap-frozen invasive breast carcinomas were immunostained with monoclonal antibodies to Cathepsin D (CD), a protease believed to mediate extracellular matrix dissolution, and Type IV collagen, a constituent of basal lamina (BL). Most cases (48/81, 53%) exhibited focal, patchy BL distribution (1+) around tumor cell nests, although subsets with diffuse continuous (2+) peritumoral sheets (15/81, 19%) or near complete absence (0+, 23/81, 28%) were also observed. Elaboration of BL was correlated with favorable morphologic differentiation (0+ BL-57% poorly differentiated vs. 2+ BL-13% poorly differentiated, p = .01), absence of nodal or systemic metastases (0+ BL-78% metastatic vs. 2+ BL-40% metastatic, p = .02), and improved disease-free survival (0+ BL-63% recurred vs. 2+ BL-20% recurred, p = .05). In addition, neoplastic cells expressed CD more frequently in tumors which lacked detectable BL synthesis (0+ BL-91% CD+ vs. 2+ BL-57% CD+, p = .03). The observed relationships between morphologic growth pattern, BL synthesis and CD expression imply conventional grading in large parts reflects activity or extent of host tissue invasion by a given neoplasm. Widespread but heterogeneous distribution of BL in breast tumors also suggests partial equilibrium between neoplastic and host tissues in most cases.

Histopathologic and flow-cytometric analysis of neoplastic and benign "background" tissue in breast carcinoma resections

Two-color, multiparametric synthesis phase fraction (SPF) analysis of cytokeratin-labeled epithelial cells was flow cytometrically performed on both benign (SPFb) and malignant tissue samples (if available, SPFt) from 132 mastectomy/lumpectomy specimens. These data were then correlated with clinicopathologic features, including (1) tumor differentiation, (2) the proportion of tumor comprised of duct carcinoma-in situ (DCIS), and (3) the histology of accompanying benign breast tissue, classified by predominant microscopic pattern as intact, normal terminal duct lobular units (NTDLU, 34% of cases), atrophic (AT, 33% of cases), proliferative fibrocystic (PFC, 26% of cases), and non-proliferative fibrocystic (NPFC, 7% of cases). SPFt was inversely correlated with extent of DCIS (DCIS =0 – 20% tumor volume – 12.7% mean SPFt, vs. DCIS >20% tumor volume – 6.4% mean SPFt, p = 0.001). SPFt also correlated with the histology of background benign breast tissue (NTDLU – 14.8% mean SPFt vs. AT – 6.9% mean SPFt vs. PFC – 12.7% mean SPFt, p = 0.05) but it did not correlate with patient age or SPFb (overall mean =0.73%). SPFb was correlated with patient age (>56 yr – 0.59% mean SPFb vs. < yr – 0.84% mean SPFb, p = 0.02), with background histology (NTDLU – 1.1% mean SPFb vs. AT – 0.43% mean SPFb vs. PFC – 0.70% mean SPFb, p < 0.02) and with the grade of the neoplasm (well/moderate – 0.58% mean vs. poorly differentiated – 0.85% mean, p = 0.04). Patients having a background of PFC were significantly older than patients with a background of NTDLU (45.2 yr vs. 60.2 yr, p = 0.01). We conclude: (1) breast carcinomas arising from a background of more actively cycling pre-involutional or proliferative fibrocystic epithelium have a greater proliferative fraction than tumors arising from atrophic epithelium, implying that the differentiation status of target cells may impact the effect(s) of tumorigenic events; (2) PFC may represent delayed, abnormal or interrupted involution rather than a hyperproliferative state relative to NTDLU, suggesting that it facilitates neoplasia by extending the period of exposure to promoter agents such as endogenous hormones, and (3) lower SPFt in breast neoplasia with more abundant “residual” DCIS may reflect a lengthier pre-invasive disease interval due to intrinsically less aggressive phenotype.