Is apocrine differentiation in breast carcinoma of prognostic significance?

Triple-Negative Apocrine Carcinomas: Toward a Unified Group With Shared Molecular Features and Clinical Behavior

Triple-negative apocrine carcinomas (TNACs) are rare breast tumors with limited studies evaluating their molecular characteristics and clinical behavior. We performed a histologic, immunohistochemical, genetic, and clinicopathologic assessment of 42 invasive TNACs (1 with a focal spindle cell component) from 41 patients, 2 pure apocrine ductal carcinomas in situ (A-DCIS), and 1 A-DCIS associated with spindle cell metaplastic carcinoma (SCMBC). All TNACs had characteristic apocrine morphology and expressed androgen receptor (42/42), gross cystic disease fluid protein 15 (24/24), and CK5/6 (16/16). GATA3 was positive in most cases (16/18, 89%), and SOX10 was negative (0/22). TRPS1 was weakly expressed in a minority of tumors (3/14, 21%). Most TNACs had low Ki67 proliferation (≤10% in 67%, 26/39), with a median index of 10%. Levels of tumor infiltrating lymphocytes were low (≤10% in 93%, 39/42, and 15% in 7%, 3/42). Eighteen percent of TNACs presented with axillary nodal metastasis (7/38). No patients treated with neoadjuvant chemotherapy achieved pathologic complete response (0%, 0/10). Nearly all patients with TNAC (97%, n = 32) were without evidence of disease at the time of study (mean follow-up of 62 months). Seventeen invasive TNACs and 10 A-DCIS (7 with paired invasive TNAC) were profiled by targeted capture-based next-generation DNA sequencing. Pathogenic mutations in phosphatidylinositol 3-kinase pathway genes PIK3CA (53%) and/or PIK3R1 (53%) were identified in all TNACs (100%), including 4 (24%) with comutated PTEN. Ras-MAPK pathway genes, including NF1 (24%), and TP53 were mutated in 6 tumors each (35%). All A-DCIS shared mutations, such as phosphatidylinositol 3-kinase aberrations and copy number alterations with paired invasive TNACs or SCMBC, and a subset of invasive carcinomas showed additional mutations in tumor suppressors (NF1, TP53, ARID2, and CDKN2A). Divergent genetic profiles between A-DCIS and invasive carcinoma were identified in 1 case. In summary, our findings support TNAC as a morphologically, immunohistochemically, and genetically homogeneous subgroup of triple-negative breast carcinomas and suggest overall favorable clinical behavior.

Reduction of AZGP1 predicts poor prognosis in esophageal squamous cell carcinoma patients in Northern China

BACKGROUND

As a key regulator in lipid mobilization, AZGP1 has been reported to play a significant role in various cancers. This study was carried out to investigate the role of AZGP1 in the development of esophageal squamous cell carcinoma (ESCC) patients in Northern China.

MATERIALS AND METHODS

Through the application of quantitative real-time polymerase chain reaction and immunohistochemical staining, AZGP1 expression in ESCC tissues from Northern China was examined.

RESULTS

Decreased expression of AZGP1 was observed in ~60% ESCC patients. AZGP1 downregulation was significantly associated with lymph node metastasis (P=0.035), advanced clinical stage (P=0.018), poor prognosis for 5-year disease-specific survival (DSS; P<0.001), local recurrence-free survival (LRFS; P=0.016), and metastasis-free survival (MeFS; P=0.014). In addition, Cox multivariate analysis revealed that AZGP1 downregulation remained to be an independent prognosticator for shorter DSS (P=0.001), LRFS (P=0.011), and MeFS (P=0.004).

CONCLUSION

AZGP1 might be a candidate tumor suppressor and a potential novel prognostic biomarker for ESCC patients in Northern China.

Loss of androgen receptor expression predicts early recurrence in triple-negative and basal-like breast cancer

Treatment of triple-negative invasive breast cancers, defined by the absence of estrogen and progesterone receptors and c-erbB2 expression, remains challenging. Androgen receptor, a member of the nuclear receptor superfamily that is involved in signaling pathways regulating cell proliferation, has been implicated in breast tumorigenesis. We immunohistochemically examined the expression of androgen receptor, basal markers (CK14, 34βE12) and EGFR in 699 triple-negative invasive breast cancers in tissue microarrays using the streptavidin-biotin method, and correlated the findings with clinical outcome. Positive androgen receptor expression was defined as staining of 1% or more of tumor cell nuclei. Survival outcomes were estimated with the Kaplan-Meier method and compared between groups with log-rank statistics. Cox proportional hazards models were used to determine the effect of androgen receptor on survival outcomes. Immunohistochemical positivity was observed in 38% of tumors, with the proportion of stained tumor cells ranging from 1 to 95% (mean 29%, median 10%). Androgen receptor expression was inversely associated with histologic grade and mitotic score. CK14, 34βE12 and EGFR confirmed 85% of cases to be basal-like, without significant association of basal-like phenotype with androgen receptor expression. Disease-free survival was significantly better in androgen receptor-positive triple-negative breast cancer, with a trend for improved overall survival. Decreased recurrence likelihood in both triple-negative and basal-like tumors (hazard ratio, 0.704; 95% confidence intervals, 0.498-0.994; P=0.0464; and hazard ratio, 0.675; 95% confidence intervals, 0.468-0.974; P=0.0355, respectively) was noted within 5 years of diagnosis but not thereafter. Our study suggests that loss of androgen receptor in triple-negative breast cancers augurs a worse prognosis, including those with basal-like features. More work in elucidating its relationship with mechanisms of progression, as well as trials of targeted treatment for androgen receptor-expressing triple-negative tumors, needs to be performed.

AZGP1 and SPDEF mRNA expression differentiates breast carcinoma from ovarian serous carcinoma

The ANPEP, AZGP1, and SPDEF genes were previously found to be overexpressed in breast compared to ovarian carcinoma effusions. The present study validated this finding in a larger cohort consisting of both primary and metastatic tumors. ANPEP, AZGP1, and SPDEF mRNA expression was investigated in 83 breast carcinomas (57 primary carcinomas and 26 effusions) and 40 ovarian carcinomas (20 primary carcinomas and 20 effusions) using qPCR. ANPEP protein expression was immunohistochemically analyzed in 53 breast carcinoma effusions and patient-matched primary carcinomas (n = 25) and lymph node metastases (n = 16). mRNA and protein levels were studied for association with tumor type and anatomic site, and for clinical role in breast carcinoma. AZGP1 and SPDEF mRNA was overexpressed in breast compared to ovarian carcinoma (both p < 0.001). AZGP1 mRNA was overexpressed in primary breast carcinoma compared to effusions (p < 0.001), with opposite findings for ANPEP (p = 0.044). AZGP1 mRNA expression correlated with positive ER status (p = 0.032) and grade 1 histology (p = 0.011), whereas SPDEF mRNA levels were associated with positive ER (p = 0.002) and PR (p = 0.013) status and tamoxifen treatment (p = 0.004). ANPEP protein expression was higher in breast carcinoma effusions compared to primary tumors and lymph node metastases (both p = 0.001). ANPEP, AZGP1, and SPDEF levels were unrelated to disease-free or overall survival. This is the first study documenting ANPEP, AZGP1, and SPDEF expression in breast carcinoma effusions. AZGP1 and SPDEF may be novel molecular markers for the differentiation of breast from ovarian carcinoma. ANPEP may be involved in breast carcinoma progression in view of its overexpression in effusions compared to solid specimens.

Zinc alpha 2-glycoprotein: a multidisciplinary protein

Zinc alpha 2-glycoprotein (ZAG) is a protein of interest because of its ability to play many important functions in the human body, including fertilization and lipid mobilization. After the discovery of this molecule, during the last 5 decades, various studies have been documented on its structure and functions, but still, it is considered as a protein with an unknown function. Its expression is regulated by glucocorticoids. Due to its high sequence homology with lipid-mobilizing factor and high expression in cancer cachexia, it is considered as a novel adipokine. On the other hand, structural organization and fold is similar to MHC class I antigen-presenting molecule; hence, ZAG may have a role in the expression of the immune response. The function of ZAG under physiologic and cancerous conditions remains mysterious but is considered as a tumor biomarker for various carcinomas. There are several unrelated functions that are attributed to ZAG, such as RNase activity, regulation of melanin production, hindering tumor proliferation, and transport of nephritic by-products. This article deals with the discussion of the major aspects of ZAG from its gene structure to function and metabolism.

Molecular pathology of breast apocrine carcinomas: A protein expression signature specific for benign apocrine metaplasia

Breast cancer is a heterogeneous disease that encompasses a wide range of histopathological types including: invasive ductal carcinoma, lobular carcinoma, medullary carcinoma, mucinous carcinoma, tubular carcinoma, and apocrine carcinoma among others. Pure apocrine carcinomas represent about 0.5% of all invasive breast cancers according to the Danish Breast Cancer Cooperative Group Registry, and despite the fact that they are morphologically distinct from other breast lesions, there are at present no standard molecular criteria available for their diagnosis. In addition, the relationship between benign apocrine changes and breast carcinoma is unclear and has been a matter of discussion for many years. Recent proteome expression profiling studies of breast apocrine macrocysts, normal breast tissue, and breast tumours have identified specific apocrine biomarkers [15-hydroxyprostaglandin dehydrogenase (15-PGDH) and hydroxymethylglutaryl coenzyme A reductase (HMG-CoA reductase)] present in early and advanced apocrine lesions. These biomarkers in combination with proteins found to be characteristically upregulated in pure apocrine carcinomas (psoriasin, S100A9, and p53) provide a protein expression signature distinctive for benign apocrine metaplasias and apocrine cystic lesions. These studies have also presented compelling evidence for a direct link, through the expression of the prostaglandin degrading enzyme 15-PGDH, between early apocrine lesions and pure apocrine carcinomas. Moreover, specific antibodies against the components of the expression signature have identified precursor lesions in the linear histological progression to apocrine carcinoma. Finally, the identification of proteins that characterize the early stages of mammary apocrine differentiation such as 15-PGDH, HMG-CoA reductase, and cyclooxygenase 2 (COX-2) has opened a window of opportunity for pharmacological intervention, not only in a therapeutic manner but also in a chemopreventive setting. Here we review published and recent results in the context of the current state of research on breast apocrine cancer.

'Pure' invasive apocrine carcinoma of the breast: a new clinicopathological entity?

Invasive apocrine carcinoma (IAC) of the breast has a similar prognosis to infiltrating ductal carcinoma not otherwise specified (IDC-NOS). The existence of a pure IAC subtype (PIAC) and its possible prognostic implications have not been fully investigated. To this end, pathological inclusion criteria for the diagnosis of PIAC were defined and three pathologists reviewed their slides blind to identify it. To assess its clinical behavior, a case-control evaluation was performed, for which 122 cases were selected. There was 100% agreement among the pathologists on the diagnosis: PIAC was identified in 37 cases and IDC-NOS, in 68, while 17 cases were categorized as complex IAC. The probability of 6-year survival was 0.72 for PIAC and 0.52 for IDC-NOS (P=0.02), and was still better after adjustment for tumor grade and axillary status. PIAC may be a distinct clinicopathological entity with a less aggressive behavior than high-grade IDC-NOS and might be regarded as an independent prognostic factor in early breast cancer.

Androgen and estrogen receptor mRNA status in apocrine carcinomas

Eleven pure apocrine carcinomas (8 breast, 2 vulvar, 1 axillary) were evaluated for the presence of androgen and estrogen receptor mRNA. These immunohistochemically androgen receptor positive and estrogen receptor negative cases were microdissected and analyzed by the reverse transcription polymerase chain reaction for the presence of receptor message. Nine of these 11 estrogen receptor (ER) negative lesions were found to contain the ER mRNA through the first intron splice region. In 4 of the 11 cases, the androgen receptor (AR) mRNA could not be shown even though the protein was detected immunohistochemically. In the other seven, AR mRNA was identified. This indicates that the mechanism for production of the estrogen receptor is intact and functional in most cases through the first transcriptional splice region. Therefore, the immunohistochemical absence of the estrogen receptor in apocrine cells cannot be explained by an abnormal message at these common sites and should be sought beyond these points.

Androgen receptor CAG repeat lengths in ductal carcinoma in situ of breast, longest in apocrine variety

CAG repeat number in the androgen receptor (AR) has been associated with decreased prostate cancer risk, and AR expression has been found in female breast cancer, often associated with apocrine differentiation. Because trinucleotide expansion can alter gene expression and protein function, we hypothesized that it might occur in breast neoplasms. We used a repeat expansion detection technique to determine CAG repeat lengths in DNA from breast biopsies. Three lesion types were microdissected: fibroadenoma (48 cases), ductal carcinoma in situ (DCIS, 24 cases), and invasive mammary carcinoma (18 cases). The maximum number of CAG repeats in either allele of each patient in these three groups was compared. Microsatellite repeat lengths in DCIS were longer than in fibroadenomas or invasive carcinomas (P= 0.017 comparing DCIS vs invasive carcinomas). Two cases of apocrine DCIS had very long repeat lengths, both exhibiting microsatellite lengths at the longest range of normal (32 and 33). Inherited differences in AR CAG length might influence the transition from DCIS to invasive breast cancer, perhaps by modulating function of AR in breast tissue. AR microsatellite polymorphisms could influence cellular differentiation in DCIS lesions, promoting formation of the apocrine subtype in the presence of longer CAG repeats.

Histiocytoid breast carcinoma: histological, immunohistochemical, ultrastructural, cytological and clinicopathological studies

Histiocytoid breast carcinoma (HBC) is a rare variant of breast carcinoma and often causes a diagnostic dilemma because of its histological similarities to some types of breast cancer and benign lesions. To elucidate the incidence of HBC and its biological properties, histological specimens from 1010 breast cancer patients treated at Yokohama Minami Kyosai Hospital between 1972 and 1996 were reviewed. Three cases of pure HBC and three cases of combined HBC (two with pleomorphic lobular carcinoma and one with apocrine ductal carcinoma) were found, yielding an incidence of 0.3% for each. Two of the three pure HBC cases contained foci of in situ lobular carcinoma. Targetoid and Indian file invasive patterns, the features characteristic of lobular carcinoma, were present in all three pure HBC cases and in two of the three combined HBC with pleomorphic lobular carcinoma. These results, together with those of previous studies, suggested that the majority of HBC are of lobular origin, although the apocrine ductal origin is also possible in a small number of HBC. Diastase-resistant periodic acid-Schiff-positive granules and granular immunoreactivities for gross cystic disease fluid protein-15 (GCDFP-15) were characteristic of the histiocytoid tumor cells in both the pure and combined HBC, suggesting the apocrine differentiation of tumor cells. All three pure HBC cases were in stage 1 and were free of the disease for up to 5 years and 1 month after the lumpectomy. Thus, the prognosis of HBC appears to be dependent on the stage of the disease and may not always be poor, as indicated by the original report mentioning a preferential eyelid metastasis.

Ductal carcinoma in situ of the breast with apocrine cytology: definition of a borderline category

Papillary patterns of apocrine cells are frequent in benign breast biopsies and pose little diagnostic difficulty when the classic apocrine cytology is present. Dilemmas in diagnosis do occur, however, when the usual papillary patterns of hyperplastic apocrine epithelium are absent in hyperplastic lesion, particularly if it is extensive, presents more complex patterns, and/or lacks usual nuclear features. We classified lesions with nonclassic apocrine features into diagnostic categories to separate those with malignant potential from those that are truly benign. We selected 54 such cases sent in consultation over a 2-year period (1989 to 1991). We applied two sets of criteria: nuclear patterns (usual, borderline, and as seen in ductal carcinoma in situ) and extent of lesion (< mm, 4 to 8 mm, and > 8 mm). The cases were categorized into diagnostic groups defined by these criteria of extent of lesion and cytologic features. We believe that application of these criteria recognizing borderline features to unusual, apocrine lesions fosters reproducibility in diagnosis and thus predictability of clinical outcome. We found only 10 cases to fit into borderline categories after use of the two criteria. The clinical utility of this suggested diagnostic stratification will require follow-up studies for linkage of criteria to clinical outcomes.

Zn-alpha 2-glycoprotein levels in breast cancer cytosols and correlation with clinical, histological and biochemical parameters

Zn-alpha 2-glycoprotein (Zn-alpha 2-gp), a protein present at high levels in breast cyst fluid, has been measured in 104 breast tumour cytosols by using an immunoenzymatic assay. Concentrations of Zn-alpha 2-gp ranged from 0 to 23.5 micrograms/mg of total soluble protein, with an average value of 2.4 micrograms/mg. There was no significant correlation between Zn-alpha 2-gp and menopausal status, tumour size or lymph node involvement, or between this protein and biochemical parameters such as oestrogen receptor, cathepsin D or pS2 levels. However, there was a significant association between Zn-alpha 2-gp and histological grade of tumours, with higher Zn-alpha 2-gp levels in well-differentiated tumours (mean 4.6 micrograms/mg) than in moderately (1.8 micrograms/mg) or poorly (0.9 micrograms/mg) differentiated tumours. On the basis of these results, we propose that Zn-alpha 2-gp may be considered as a biochemical marker of differentiation in breast cancer.

Zinc alpha-2 glycoprotein levels in serum and breast fluids: a potential marker of apocrine activity

Zinc alpha-2 glycoprotein (ZnGP) was measured in human breast microcysts, breast secretions, breast cyst fluid and serum. Detectable amounts of ZnGP were found in all fluids but the highest levels were found in microcysts. Apocrine macrocysts had a higher ZnGP level than flattened macrocysts. In both cysts and secretions levels of ZnGP correlated with those of dehydroepiandrosterone sulphate. Levels were significantly higher in cyst fluids from women who developed further cysts during follow-up compared with those in fluid from women who did not. Concentrations of ZnGP in serum from breast cancer patients were significantly higher than controls but not women with breast cysts. Women with node positive breast cancer had higher serum levels compared with those in node negative patients. Women with more advanced breast cancer had higher serum ZnGP levels than those with earlier disease. ZnGP is a serum and breast marker of apocrine activity and may prove to be a useful prognostic marker in breast cancer.