P1-09-03: Prevalence of Germline TP53 Mutations in Young Women with HER2−Positive Breast Cancer

Background: Li Fraumeni syndrome is a rare inherited cancer susceptibility condition associated with germline mutations in the TP53 gene, in which breast cancer (BC) is the most frequent tumor. The prevalence of TP53 mutations in population-based series of very young onset BC (<30 years at diagnosis) ranges from <1% to approximately 7%1-4. Recent data show that BC in patients carrying a germline TP53 mutation are commonly HER2 amplified (63-83%)5-7. In this study, we assessed the prevalence of germline TP53 mutations in women with HER2 positive BC diagnosed age ≤ 50 years.

Material & Methods: We identified 347 women with invasive HER2 positive BC diagnosed at age ≤ 50 years using the Clinical Operations and Research Information System (CORIS) at the Dana Farber Cancer Institute. Information on age at diagnosis, histology, hormone receptor and HER2 status as well as personal and family cancer history was confirmed from medical records. 129 patients were excluded for various reasons, including a cancer diagnosis prior to the BC and a documented BRCA1/2 mutation. A combination of Exon Grouping Analysis (EGAN) and Sanger sequencing for detection of TP53 mutations in exons 2–11 including surrounding intronic sequence was performed on 218 germline DNA samples. Multiplex Ligation-dependent Probe Amplification (MLPA) analysis for the detection of TP53 deletions or duplications is ongoing.

Results: A germline TP53 mutation was identified in 4 women diagnosed at age ≤ 50 years (1.8%, 95%CI 0.5−4.6). At BC diagnosis, they were 23, 32, 44 and 50 years. Two BC were ER+/PR+, HER2+ and 2 were ER-/PR-, HER2+. Estimate of prevalence of germline TP53 mutations by age at BC diagnosis are: age ≤ 35, 2/41 (4.9%, 95%CI 0.6−16.6), and age ≤ 45 3/168 (1.8%, 95%CI 0.4−5.1). Among the women with germline TP53 mutations, 2 met the Chompret criteria8 and none the classic LFS criteria.

Discussion: TP53 mutations were identified in a cohort of women with HER2+ BC at young age. As expected, the frequency is higher in younger women, but mutations were seen in all age groups that were evaluated. None of these women met classic LFS criteria by family history. Consideration of TP53 testing should be given to women diagnosed below age 35 who are negative for BRCA1/2 mutations regardless of family history. Analysis of other series will be helpful in reaching more stable estimates of the prevalence of mutation carriers among patients with HER2+ BC at young age.

1. Sidransky D et al. Cancer Res. 1992; 52:2984–2986.

2. Borresen AL et al. Cancer Res.1992; 52:3234–3236.

3. Lalloo F et al. Lancet 2003; 361:1101–02

4. Gonzalez KD et al. J Clin Oncol 2009;27(8):1250–6

5. Wilson JR et al. J Med Genet 2010;47(11):771–774.

6. Melhem-Bertrandt A et al: San Antonio Breast Cancer Symposium 2010: P3-12-01.

7. Masciari S et al: J Clin Oncol 29: 2011 (suppl; abstr 1519)

8. Tinat J et al. J Clin Oncol. 2009;27(26):e108–9

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-09-03.

Nipple fluid carcinoembryonic antigen and prostate-specific antigen in cancer-bearing and tumor-free breasts

PURPOSE

Mammograms and breast examinations are established methods for early breast cancer detection. Routine mammography screening reduces breast cancer mortality among women ages > or = 50 years, but additional screening methods are needed. We and others have found high levels of carcinoembryonic antigen (CEA) and prostate-specific antigen (PSA) in nipple aspirate fluids (NAFs), but the usefulness for these bio-markers for early breast cancer detection is unknown.

PATIENTS AND METHODS

NAFs from one or both breasts of 388 women were analyzed for CEA, PSA, and albumin levels. The study included 44 women with newly diagnosed invasive breast cancers, 67 women with proliferative breast lesions (ductal and lobular carcinoma in situ and atypical ductal hyperplasia), and 277 controls without these breast lesions. Analyses were conducted using the log(10)-transformed CEA and PSA levels to normalize the distributions of these tumor markers.

RESULTS

Nipple fluid CEAs are significantly higher for cancerous breasts than tumor-free breasts (median 1,830 and 1,400 ng/mL, respectively; P <.01). However, at 90% specificity of the assay (CEA = 11,750 ng/mL), the corresponding sensitivity for cancer detection is 32%. CEA levels are not significantly different for breasts with proliferative lesions compared with tumor-free breasts. Nipple fluid PSAs do not differ by tumor status. Analyses of NAF albumin-standardized CEAs and PSAs yield similar results. Nipple fluid CEA and PSA titers are correlated in the affected and unaffected breast of women with unilateral lesions.

CONCLUSION

Nipple fluid CEAs are higher for breasts with untreated invasive cancers, but the test sensitivity is low. Nipple fluid PSA titers do not seem to be useful for breast cancer detection.

Novel p53 splice site mutations in three families with Li-Fraumeni syndrome

Germline mutations in the p53 tumor suppressor gene predispose to a variety of cancers in families with Li-Fraumeni syndrome. Most germline p53 mutations observed to date cause amino acid substitutions in the protein's central sequence-specific DNA binding domain. Outside this conserved core region, however, we found novel alterations in sequences that regulate precursor mRNA splicing in three Li-Fraumeni syndrome families. Two splice site mutations affected the consensus sequence at the splice donor sites of introns 1 and 9, and produced unstable variant transcripts in normal cells. A third mutation at the splice acceptor site of intron 9 generated splicing at a cryptic acceptor site in intron 9. These splice site alterations emphasize the need to examine both noncoding and untranslated regions of the p53 gene for germline mutations in Li-Fraumeni syndrome families. Oncogene (2000) 19, 4230 - 4235

Heterozygous germ line hCHK2 mutations in Li-Fraumeni syndrome

The hCHK2 gene encodes the human homolog of the yeast Cds1 and Rad53 G2 checkpoint kinases, whose activation in response to DNA damage prevents cellular entry into mitosis. Here, it is shown that heterozygous germ line mutations in hCHK2 occur in Li-Fraumeni syndrome, a highly penetrant familial cancer phenotype usually associated with inherited mutations in the TP53 gene. These observations suggest that hCHK2 is a tumor suppressor gene conferring predisposition to sarcoma, breast cancer, and brain tumors, and they also provide a link between the central role of p53 inactivation in human cancer and the well-defined G2 checkpoint in yeast.

Regulation of angiogenin expression in human HepG2 hepatoma cells by mediators of the acute-phase response

Angiogenin is a potent inducer of neovascularization in vivo. However, like other angiogenic molecules, its specific physiologic roles and mechanisms regulating its expression remain to be elucidated. Angiogenin is a liver-derived component of normal serum whose concentration can increase in various disease states. This suggests that it might participate in the acute-phase response. In an initial study we showed that angiogenin protein and mRNA levels transiently increased in mice following an acute inflammatory stimulus. We now report that IL-6, a major inducer of acute-phase proteins, stimulates the synthesis and secretion of angiogenin protein in human HepG2 cells within 24 hr following treatment, an effect enhanced by dexamethasone. IL-6 also increases the amount of angiogenin mRNA without altering its half-life. This increase, suppressible by cycloheximide, peaks at 12 hr following stimulation and returns to basal levels by 48 hr. IL-1 alone slightly decreases the basal production of angiogenin protein and mRNA, but essentially abolishes the response to IL-6 in the absence or presence of dexamethasone. This antagonistic effect by IL-1 on IL-6 activity is not a result of changes in mRNA stability nor is it dependent on new protein synthesis. Thus, the combined effects of IL-6, IL-1, glucocorticoids, and perhaps other related factors may specifically control angiogenin expression. Since angiogenin is regulated in a manner similar to that of acute phase proteins both in vitro and in vivo, it may play a role in the host response to injury.

Carcinoembryonic antigen in breast nipple aspirate fluid

New diagnostic tools are needed to complement mammography and physical examinations for early detection of breast cancer, particularly among younger women. We evaluated the tumor biomarker, carcinoembryonic antigen (CEA), in 215 nipple aspirate fluid (NAF) samples collected from one or both breasts of 147 women, ages 27-87 years. Most subjects were recruited at the time of mammography examination. The 215 nipple fluid CEAs range from undetectable levels to 8400 ng/ml (median, 1100 ng/ml). Normal serum CEA levels are less than 6 ng/ml. There are no significant differences between the CEAs in fluid from normal breasts (112 samples) and breasts with various histories of tumors (total, 103 samples). Analyses for determinants of CEAs in fluids from normal breasts show higher levels among current smokers (P = 0.03) and marginal elevations among nulliparous women (P = 0.07). CEAs in these samples are not correlated with age, menopausal status, current hormone use, prior breastfeeding, or family history of breast cancer. Follow-up studies of these women and comparisons of CEAs in fluids from normal and cancer-containing breasts will help clarify whether this biomarker is useful for risk assessment or early cancer detection.

Angiogenin is regulated in vivo as an acute phase protein

Angiogenin (Ang), a potent mediator of neovascularization, is secreted by and is critical for the growth of human tumor cells in experimental animals. However, control mechanisms that regulate its expression under normal physiological conditions have not been described. We have determined previously that Ang is present in normal human serum and that its concentration, normally falling within a narrow range, can vary widely in hospitalized patients. This observation, plus a report that Ang is synthesized in the adult liver, led us to investigate whether it can be regulated as an acute phase protein (APP). Ang concentration in the serum of mice placed into the acute phase by injection with 3% thioglycollate do indeed increase transiently as is typical for APPs. Moreover, a liver-specific rise and subsequent fall in Ang mRNA transcripts also follows entrance into acute inflammation. We conclude that Ang can be regulated in vivo in a manner that is characteristic of an APP and, therefore, may contribute to the angiogenic component of tissue repair that accompanies host response to inflammation and trauma. To our knowledge, this is the first demonstration that a well-characterized angiogenic mediator can be regulated as an APP.

Molecular epidemiology study of a suspected community cluster of childhood cancers

We investigated the report of a community cluster of cancers in 33 children, which included two siblings known to have dominantly inherited Li-Fraumeni syndrome and a germline p53 mutation. After defining criteria for inclusion in the cluster, the 12 eligible childhood cancer probands diagnosed between 1980 and 1989 were not excessive (expected, ten cases). The corresponding childhood cancer mortality rates for the community fluctuated between 1950 and 1989 and were not increased overall. However, three additional probands had family histories of childhood cancer that suggested a forme fruste of Li-Fraumeni syndrome. The epidemiological data suggested a geographic cluster of this rare hereditary disorder, but absence of germline p53 mutation in the three other multicase families indicates genetic heterogeneity. Laboratory studies can assist analyses of suspected clusters, although investigations of geographic clusters of hereditary cancers raise complex issues of confidentiality and protection of affected individuals, their families, and the community.

CD4+ T cell activation in multiple sclerosis

Interleukin-2 (IL-2) production by CD4-enriched T cells from multiple sclerosis (MS) patients and normal individuals stimulated with concanavalin A (conA) and/or autologous and allogeneic B lymphoid cell lines (B-LCL) was evaluated 24, 48 and 96 h after stimulation. ConA-stimulated CD4+ cells from MS patients did not produce significantly more IL-2 than normal CD4+ cells. In contrast, autologous B-LCL-induced IL-2 production by MS CD4+ cells significantly (P = 0.026) exceeded that produced by normal CD4+ cells identically stimulated after 24 h in culture. Differences in IL-2 production by CD4+ cells from MS patients reached highest significance using allogeneic B-LCL, whose stimulatory capacity was similar, whether established from normal individuals or MS patients. This increased IL-2 production in response to B-LCL may represent a supranormal response of CD4+ cells from MS patients to class II major histocompatibility (MHC)-associated stimuli. It suggests that the deficiency of suppressor T cell functions postulated to play a role in MS does not arise from a lack of IL-2 induction and might indicate that bursts of IL-2 production could play a role in MS.