<?xml version="1.0" encoding="UTF-8"?><SubstanceDefinition xmlns="http://hl7.org/fhir">
  <id value="her2"/>
  <meta>
    <security>
      <system value="http://terminology.hl7.org/CodeSystem/v3-ActReason"/>
      <code value="HTEST"/>
      <display value="test health data"/>
    </security>
  </meta>
  <identifier>
    <system value="https://www.uniprot.org"/>
    <value value="P04626"/>
  </identifier>
  <status>
    <coding>
      <system value="http://hl7.org/fhir/publication-status"/>
      <code value="active"/>
      <display value="Active"/>
    </coding>
  </status>
  <classification>
    <coding>
      <system value="http://example.europa.eu/fhir/SubstanceType"/>
      <code value="protein"/>
      <display value="Protein"/>
    </coding>
  </classification>
  <domain>
    <coding>
      <system value="http://example.europa.eu/fhir/Domain"/>
      <code value="human"/>
      <display value="Human use"/>
    </coding>
  </domain>
  <description value="Human HER2 (ErbB2, receptor tyrosine-protein kinase erbB-2). A transmembrane receptor of the EGFR family, frequently overexpressed in breast and gastric cancers. The molecular target of trastuzumab and other HER2-directed therapies."/>
  <code>
    <code>
      <coding>
        <system value="https://www.uniprot.org"/>
        <code value="P04626"/>
        <display value="ERBB2_HUMAN"/>
      </coding>
    </code>
  </code>
  <name>
    <name value="Receptor tyrosine-protein kinase erbB-2"/>
    <preferred value="true"/>
    <language>
      <coding>
        <system value="urn:ietf:bcp:47"/>
        <code value="en"/>
        <display value="English"/>
      </coding>
    </language>
  </name>
  <name>
    <name value="HER2"/>
    <preferred value="false"/>
  </name>
  <name>
    <name value="ErbB-2"/>
    <preferred value="false"/>
  </name>
  <name>
    <name value="CD340"/>
    <preferred value="false"/>
  </name>
  <protein>
    <sequenceType>
      <coding>
        <system value="http://hl7.org/fhir/substance-sequence-type"/>
        <code value="complete"/>
        <display value="Complete"/>
      </coding>
    </sequenceType>
    <numberOfSubunits value="1"/>
    <subunit>
      <subunit value="1"/>
      <length value="1255"/>
    </subunit>
    <gene>
      <sequenceOrigin>
        <coding>
          <system value="http://hl7.org/fhir/gene-sequence-origin"/>
          <code value="human"/>
          <display value="Human"/>
        </coding>
      </sequenceOrigin>
      <gene>
        <concept>
          <coding>
            <system value="http://www.genenames.org"/>
            <code value="ERBB2"/>
            <display value="Erb-B2 receptor tyrosine kinase 2"/>
          </coding>
        </concept>
      </gene>
    </gene>
  </protein>
</SubstanceDefinition>