{"id":175,"date":"2026-07-01T07:52:45","date_gmt":"2026-07-01T07:52:45","guid":{"rendered":"https:\/\/blogs.imperial.ac.uk\/my-path\/?p=175"},"modified":"2026-07-01T07:53:36","modified_gmt":"2026-07-01T07:53:36","slug":"bsep-bile-salt-export-pump-immunohistochemistry","status":"publish","type":"post","link":"https:\/\/blogs.imperial.ac.uk\/my-path\/2026\/07\/01\/bsep-bile-salt-export-pump-immunohistochemistry\/","title":{"rendered":"BSEP (Bile Salt Export Pump) Immunohistochemistry"},"content":{"rendered":"<p class=\"font-claude-response-body break-words whitespace-normal\">Bile Salt Export Pump (BSEP) is an ATP-binding cassette transporter protein (encoded by <em>ABCB11<\/em>) that functions as the major canalicular bile salt transporter in hepatocytes. In diagnostic pathology, BSEP IHC is used primarily as a canalicular marker for hepatocellular carcinoma and in the diagnosis of bile salt export pump deficiency in progressive familial intrahepatic cholestasis type 2 (PFIC2).<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal\"><strong>Hepatocellular carcinoma<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal\">BSEP shows a canalicular (&#8220;chicken-wire&#8221;) staining pattern in tumour cells, reflecting its normal physiological role as a bile salt transporter. This pattern confirms hepatocellular differentiation and helps distinguish HCC from metastatic adenocarcinoma or cholangiocarcinoma, neither of which forms canaliculi and therefore won&#8217;t show this staining pattern.<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal\">BSEP functions conceptually alongside other canalicular markers such as polyclonal CEA and CD10, and is generally considered more sensitive and specific than pCEA in some series.<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal\">Loss or reduction of BSEP staining has also been reported in poorly differentiated HCC and in some cholestatic hepatocellular lesions, so absent staining isn&#8217;t specific on its own \u2014 pattern interpretation in context matters.<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal\"><strong>Progressive Familial Intrahepatic Cholestasis Type 2<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal\">PFIC2 results from biallelic <em>ABCB11<\/em> mutations. Liver biopsy IHC typically shows absent or markedly reduced canalicular BSEP staining, supporting the diagnosis alongside clinical\/biochemical features (low-GGT cholestasis, elevated bile acids) and molecular confirmation.<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal\">A useful nuance: some <em>ABCB11<\/em> missense mutations produce a mistrafficked but partially functional protein, which can show weak\/patchy canalicular staining or an intracellular rather than purely canalicular pattern \u2014 so BSEP IHC is supportive but not strictly binary, and genetic testing remains the gold standard.<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal\">PFIC2 patients with BSEP deficiency also carry an increased risk of hepatocellular carcinoma and cholangiocarcinoma at a young age, which is relevant when assessing paediatric explant or resection specimens.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Bile Salt Export Pump (BSEP) is an ATP-binding cassette transporter protein (encoded by ABCB11) that functions as the major canalicular bile salt transporter in hepatocytes. In diagnostic pathology, BSEP IHC is used primarily as a canalicular marker for hepatocellular carcinoma and in the diagnosis of bile salt export pump deficiency in progressive familial intrahepatic cholestasis [&hellip;]<\/p>\n","protected":false},"author":1119,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[289779,1],"tags":[318396],"class_list":["post-175","post","type-post","status-publish","format-standard","hentry","category-hepato-biliary-pathology","category-uncategorized","tag-consultant"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.4 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>BSEP (Bile Salt Export Pump) Immunohistochemistry - My Path<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/blogs.imperial.ac.uk\/my-path\/2026\/07\/01\/bsep-bile-salt-export-pump-immunohistochemistry\/\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"BSEP (Bile Salt Export Pump) Immunohistochemistry - My Path\" \/>\n<meta property=\"og:description\" content=\"Bile Salt Export Pump (BSEP) is an ATP-binding cassette transporter protein (encoded by ABCB11) that functions as the major canalicular bile salt transporter in hepatocytes. In diagnostic pathology, BSEP IHC is used primarily as a canalicular marker for hepatocellular carcinoma and in the diagnosis of bile salt export pump deficiency in progressive familial intrahepatic cholestasis [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/blogs.imperial.ac.uk\/my-path\/2026\/07\/01\/bsep-bile-salt-export-pump-immunohistochemistry\/\" \/>\n<meta property=\"og:site_name\" content=\"My Path\" \/>\n<meta property=\"article:published_time\" content=\"2026-07-01T07:52:45+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2026-07-01T07:53:36+00:00\" \/>\n<meta name=\"author\" content=\"Robert Goldin\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Robert Goldin\" \/>\n\t<meta name=\"twitter:label2\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/2026\\\/07\\\/01\\\/bsep-bile-salt-export-pump-immunohistochemistry\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/2026\\\/07\\\/01\\\/bsep-bile-salt-export-pump-immunohistochemistry\\\/\"},\"author\":{\"name\":\"Robert Goldin\",\"@id\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/#\\\/schema\\\/person\\\/ae3686a35ddfab70a9ba176d3e643902\"},\"headline\":\"BSEP (Bile Salt Export Pump) Immunohistochemistry\",\"datePublished\":\"2026-07-01T07:52:45+00:00\",\"dateModified\":\"2026-07-01T07:53:36+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/2026\\\/07\\\/01\\\/bsep-bile-salt-export-pump-immunohistochemistry\\\/\"},\"wordCount\":284,\"keywords\":[\"Consultant\"],\"articleSection\":[\"Hepato-biliary Pathology\",\"Uncategorized\"],\"inLanguage\":\"en-GB\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/2026\\\/07\\\/01\\\/bsep-bile-salt-export-pump-immunohistochemistry\\\/\",\"url\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/2026\\\/07\\\/01\\\/bsep-bile-salt-export-pump-immunohistochemistry\\\/\",\"name\":\"BSEP (Bile Salt Export Pump) Immunohistochemistry - My Path\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/#website\"},\"datePublished\":\"2026-07-01T07:52:45+00:00\",\"dateModified\":\"2026-07-01T07:53:36+00:00\",\"author\":{\"@id\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/#\\\/schema\\\/person\\\/ae3686a35ddfab70a9ba176d3e643902\"},\"breadcrumb\":{\"@id\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/2026\\\/07\\\/01\\\/bsep-bile-salt-export-pump-immunohistochemistry\\\/#breadcrumb\"},\"inLanguage\":\"en-GB\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/2026\\\/07\\\/01\\\/bsep-bile-salt-export-pump-immunohistochemistry\\\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/2026\\\/07\\\/01\\\/bsep-bile-salt-export-pump-immunohistochemistry\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"BSEP (Bile Salt Export Pump) Immunohistochemistry\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/#website\",\"url\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/\",\"name\":\"My Path\",\"description\":\"Rob Goldin\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-GB\"},{\"@type\":\"Person\",\"@id\":\"https:\\\/\\\/blogs.imperial.ac.uk\\\/my-path\\\/#\\\/schema\\\/person\\\/ae3686a35ddfab70a9ba176d3e643902\",\"name\":\"Robert Goldin\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-GB\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/cbb08e649da7c1060a5cde6321602b89e9e6b9d3b9cebc668c47e2676cf28207?s=96&d=mm&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/cbb08e649da7c1060a5cde6321602b89e9e6b9d3b9cebc668c47e2676cf28207?s=96&d=mm&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/cbb08e649da7c1060a5cde6321602b89e9e6b9d3b9cebc668c47e2676cf28207?s=96&d=mm&r=g\",\"caption\":\"Robert Goldin\"},\"description\":\"I am a histopathologist based at Imperial but work one day a week in Oxford. 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