Background: Folate receptor alpha (FRA) is involved in folate accumulation and utilization, and is expressed in varying proportions in breast, ovary and parotid epithelial cells, among others. FRA overexpression by immunohistochemistry (IHC) has been shown in estrogen/progesterone receptor (ER/PR)-negative carcinoma (40-74%) and in triple-negative breast carcinoma (TNBC; 50-86%) in histological specimens of primary breast cancers. We assessed the feasibility of IHC in detecting FRA expression and its patterns and clinical significance in metastatic TNBC in fine-needle aspiration (FNA) cell blocks (CBs). Materials and Methods: Metastatic breast ductal carcinoma cases were retrospectively immunostained with FRA IHC on FNA CBs. FRA staining was scored qualitatively (+/-), by intensity (0-3) and by staining area (0-100%). Of these metastatic cases, a subset of primary breast carcinoma cases was also immunostained with FRA. The results were correlated with ER, PR and human epidermal growth factor receptor 2 (Her2/Neu) performed by routine IHC. Results: A total of 40 FNA CBs with metastatic disease were studied, including hormone (ER/PR) positive (n = 5), triple positive (n = 5), Her2/Neu-only positive (n = 5) and TNBC (n = 25). FRA IHC showed immunoreactivity with moderate positivity in only 1 (4%) TNBC. All the remaining 39 cases were negative for FRA expression. Five cases of primary TNBC were stained with FRA IHC and were negative for FRA expression. Conclusions: Our data suggest that FRA expression by IHC was rarely associated with ER/PR-negative tumors relative to ER/PR-positive tumors and, more importantly, with TNBC in FNA CBs. This finding may have a clinical significance and prognostic implications in metastatic breast carcinoma. Furthermore, 5 primary TNBC cases did not overexpress FRA by IHC. Hence, antifolate receptor therapies do not appear to be clinically relevant in TNBC based on immunostaining of FNA CBs of metastatic breast cancers.

1.
DeSantis C, Ma J, Bryan L, Jemal A: Breast cancer statistics, 2013. CA Cancer J Clin 2014;64:52-62.
2.
Bauer KR, Brown M, Cress RD, Parise CA, Caggiano V: Descriptive analysis of estrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and HER2-negative invasive breast cancer, the so-called triple-negative phenotype: a population-based study from the California Cancer Registry. Cancer 2007;109:1721-1728.
3.
Edge SB; American Joint Committee on Cancer: AJCC Cancer Staging Manual, ed 7. New York, Springer, 2010, p 648.
4.
Braxton DR, Cohen C, Siddiqui MT: Utility of GATA3 immunohistochemistry for diagnosis of metastatic breast carcinoma in cytology specimens. Diagn Cytopathol 2015;43:271-277.
5.
Chia SY, Thike AA, Cheok PY, Tan PH: Utility of mammaglobin and gross cystic disease fluid protein-15 (GCDFP-15) in confirming a breast origin for recurrent tumors. Breast 2010;19:355-359.
6.
Yan Z, Gidley J, Horton D, Roberson J, Eltoum IE, Chhieng DC: Diagnostic utility of mammaglobin and GCDFP-15 in the identification of metastatic breast carcinoma in fluid specimens. Diagn Cytopathol 2009;37:475-478.
7.
Huo L, Zhang J, Gilcrease MZ, et al: Gross cystic disease fluid protein-15 and mammaglobin A expression determined by immuno-histochemistry is of limited utility in triple-negative breast cancer. Histopathology 2013;62:267-274.
8.
Elnakat H, Ratnam M: Distribution, functionality and gene regulation of folate receptor isoforms: implications in targeted therapy. Adv Drug Deliv Rev 2004;56:1067-1084.
9.
Kelemen LE: The role of folate receptor alpha in cancer development, progression and treatment: cause, consequence or innocent bystander? Int J Cancer 2006;119:243-250.
10.
Jhaveri MS, Rait AS, Chung KN, Trepel JB, Chang EH: Antisense oligonucleotides targeted to the human alpha folate receptor inhibit breast cancer cell growth and sensitize the cells to doxorubicin treatment. Mol Cancer Ther 2004;3:1505-1512.
11.
Weitman SD, Lark RH, Coney LR, Fort DW, Frasca V, Zurawski VR, Kamen BA: Distribution of the folate receptor GP38 in normal and malignant cell lines and tissues. Cancer Res 1992;52:3396-3401.
12.
Weitman SD, Weinberg AG, Coney LR, Zurawski VR, Jennings DS, Kamen BA: Cellular localization of the folate receptor: potential role in drug toxicity and folate homeostasis. Cancer Res 1992;52:6708-6711.
13.
O'Shannessy DJ, Somers EB, Albone E, Cheng X, Park YC, Tomkowicz BE, Hamuro Y, Kohl TO, Forsyth TM, Smale R, Fu Y-S, Nicolaides NC: Characterization of the human folate receptor alpha via novel antibody-based probes. Oncotarget 2011;2:1227-1243.
14.
O'Shannessy DJ, Yu G, Smale R, Fu Y-S, Singhal S, Thiel RP, Somers EB, Vachani A: Folate receptor alpha expression in lung cancer: diagnostic and prognostic significance. Oncotarget 2012;3:414-425.
15.
Bueno R, Appasani K, Mercer H, Lester S, Sugarbaker D: The alpha folate receptor is highly activated in malignant pleural mesothelioma. J Thorac Cardiovasc Surg 2001;121:225-233.
16.
Franklin WA, Waintrub M, Edwards D, Christensen K, Prendegrast P, Woods J, Bunn PA, Kolhouse JF: New anti-lung-cancer antibody cluster 12 reacts with human folate receptors present on adenocarcinoma. Int J Cancer Suppl 1994;8:89-95.
17.
Parker N, Turk MJ, Westrick E, Lewis JD, Low PS, Leamon CP: Folate receptor expression in carcinomas and normal tissues determined by a quantitative radioligand binding assay. Anal Biochem 2005;338:284-293.
18.
Ross JF, Chaudhuri PK, Ratnam M: Differential regulation of folate receptor isoforms in normal and malignant tissues in vivo and in established cell lines. Physiologic and clinical implications. Cancer 1994;73:2432-2443.
19.
Shia J, Klimstra DS, Nitzkorski JR, Low PS, Gonen M, Landmann R, Weiser MR, Franklin WA, Prendergast FG, Murphy L, Tang LH, Temple L, Guillem JG, Wong WD, Paty PB: Immunohistochemical expression of folate receptor alpha in colorectal carcinoma: patterns and biological significance. Hum Pathol 2008;39:498-505.
20.
Wu M, Gunning W, Ratnam M: Expression of folate receptor type alpha in relation to cell type, malignancy, and differentiation in ovary, uterus, and cervix. Cancer Epidemiol Biomarkers Prev 1999;8:775-782.
21.
O'Shannessy DJ, Somers EB, Maltzman J, Smale R, Fu YS: Folate receptor alpha (FRA) expression in breast cancer: identification of a new molecular subtype and association with triple negative disease. Springer Plus 2012;1:22-30.
22.
Zhang Z, Wang J, Tacha DE, Li P, Bremer RE, Chen H, Wei B, Xiao X, Da J, Skinner K, Hicks DG, Bu H, Tang P: Folate receptor α associated with triple-negative breast cancer and poor prognosis. Arch Pathol Lab Med 2014;138:890-895.
23.
Hartmann LC, Keeney GL, Lingle WL, et al: Folate receptor overexpression is associated with poor outcome in breast cancer. Int J Cancer 2007;121:938-942.
24.
Siddiqui MT, Seydafkan S, Cohen C: GATA3 expression in metastatic urothelial carcinoma in fine needle aspiration cell blocks: a review of 25 cases. Diagn Cytopathol 2014;42:809-815.
25.
Kinsella MD, Birdsong GG, Siddiqui MT, Cohen C, Hanley KZ: Immunohistochemical detection of estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 in formalin-fixed breast carcinoma cell block preparations: correlation of results to corresponding tissue block (needle core and excision) samples. Diagn Cytopathol 2013;41:192-198.
26.
Wolff AC, Hammond ME, Hicks DG, et al: Recommendations for human epidermal growth factor 2 testing in breast cancer: American Society of Clinical Oncology/College of American Pathologists clinical practice guideline update. J Clin Oncol 2013;31:3997-4013.
27.
Kinsella MD, Nassar A, Siddiqui MT, Cohen C: Estrogen receptor (ER), progesterone receptor (PR), and HER2 expression pre- and post-neoadjuvant chemotherapy in primary breast carcinoma: a single institutional experience. Int J Clin Exp Pathol 2012;5:530-536.
28.
O'Shaughnessy J, Schwartzberg LS, Danso MA et al: A randomized phase III study of iniparib (BSI-201) in combination with gemcitabine/carboplatin (G/C) in metastatic triple-negative breast cancer (abstract). J Clin Oncol 2011;29(suppl 15):1007.
29.
Metzger-Filho O, Tutt A, de Azambuja E, Saini KS, Viale G, Loi S, Bradbury I, Bliss JM, Azim HA Jr, Ellis P, Di Leo A, Baselga J, Sotiriou C, Piccart-Gebhart M: Dissecting the heterogeneity of triple negative breast cancer. J Clin Oncol 2012;30:1879-1887.
30.
Luhrs C, Raskin CA, Durbin R, Wu B, Sadasivan E, Rothenberg SP: Transfection of a glycosylated phosphatidylinositol-anchored folate-binding protein complementary DNA provides cells with the ability to survive in low folate medium. J Clin Invest 1992;90:840-847.
31.
Kelley KM, Rowan BG, Ratnam M: Modulation of the folate receptor alpha gene by the estrogen receptor: mechanism and implications in tumor targeting. Cancer Res 2003;63:2820-2828.
32.
Dosio F, Milla P, Cattel L: EC-145, a folate-targeted Vinca alkaloid conjugate for the potential treatment of folate receptor-expressing cancers. Curr Opin Investig Drugs 2010;11:1424-1433.
33.
Pribble P, Edelman MJ: EC145: a novel targeted agent for adenocarcinoma of the lung. Expert Opin Investig Drugs 2012;21:755-761.
34.
Iwakiri S, Sonobe M, Nagai S, Hirata T, Wada H, Miyahara R: Expression status of folate receptor alpha is significantly correlated with prognosis in non-small-cell lung cancers. Ann Surg Oncol 2008;15:889-899.
35.
Toffoli G, Cernigoi C, Russo A, Gallo A, Bagnoli M, Boiocchi M: Overexpression of folate binding protein in ovarian cancers. Int J Cancer 1997;74:193-198.
36.
Toffoli G, Russo A, Gallo A, Cernigoi C, Miotti S, Sorio R, Tumolo S, Boiocchi M: Expression of folate binding protein as a prognostic factor for response to platinum-containing chemotherapy and survival in human ovarian cancer. Int J Cancer 1998;79:121-126.
37.
Garin-Chesa P, Campbell I, Saigo PE, et al: Trophoblast and ovarian cancer antigen LK26: sensitivity and specificity in immunopathology and molecular identification as a folate-binding protein. Am J Pathol 1993;142:557-567.
38.
Ross JF, Chaudhuri PK, Ratnam M: Differential regulation of folate receptor isoforms in normal and malignant tissues in vivo and in established cell lines: physiologic and clinical implications. Cancer 1994;73:2432-2443.
39.
Sasaki Y, Miwa K, Yamashita K, Sunakawa Y, Shimada K, Ishida H, Hasegawa K, Fujiwara K, Kodaira M, Fujiwara Y, Namiki M, Matsuda M, Takeuchi Y, Katsumata N: A phase I study of farletuzumab, a humanized anti-folate receptor α monoclonal antibody, in patients with solid tumors. Invest New Drugs 2015;33:332-340.
40.
Tacha D, Bremer R: Folate receptor alpha is frequently expressed in ER/PR negative and triple negative breast cancers. Mod Pathol 2013;26(suppl 2):71A.
41.
Yuan Y, Nymoen DA, Dong HP, Bjørang O, Shih I-M, Low PS, Trope' CG, Davidson B: Expression of the folate receptor genes FOLR1 and FOLR3 differentiates ovarian carcinoma from breast carcinoma and malignant mesothelioma in serous effusions. Hum Pathol 2009;40:1453-1460.
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