anchor.diff:                          "aTargets": [ mutTableIndices["pancan_mutations"] ],
                           "sClass": "center-align-td",
                           "mDataProp": function(source,type,value) {
  -                            var keyword = mutations.getValue(source[0], "key");
  -
  -                            var sum = function(a,b) { return a + b; };
  -
  -                            var total_sequenced_patients = _.chain(window.cancerStudy2NumSequencedCases)
  -                                    .values()
  -                                    .reduce(sum)
  -                                    .value();
  -
  -                            var format_percent = d3.format("%.00");
  -
                               if (type === 'display') {
                                   if (genomicEventObs.pancan_mutation_frequencies) {
  -                                    var data = genomicEventObs.pancan_mutation_frequencies[keyword];
  -
  -                                    return format_percent(_.chain(data)
  -                                            .map(function(d) { return d.count; })
  -                                            .reduce(sum)
  -                                            .value() / total_sequenced_patients);
  +
  +                                    var keyword = mutations.getValue(source[0], "key");
  +                                    var hugo = mutations.getValue(source[0], "gene");
  +                                    var byKeywordData = genomicEventObs.pancan_mutation_frequencies[keyword];
  +                                    var byHugoData = genomicEventObs.pancan_mutation_frequencies[hugo];
  +
  +                                    var invisible_container = document.getElementById("pancan_mutations_histogram_container");
  +
  +                                    $(invisible_container).empty();
  +
  +                                    PancanMutationHistogram(byKeywordData,
  +                                            byHugoData,
  +                                            window.cancerStudy2NumSequencedCases,
  +                                            invisible_container);
  +
  +                                    return "<p>foobar</p>";
  +
  +//                                    var sum = function(a,b) { return a + b; };
  +//
  +//                                    var total_sequenced_patients = _.chain(window.cancerStudy2NumSequencedCases)
  +//                                            .values()
  +//                                            .reduce(sum)
  +//                                            .value();
  +//
  +//                                    var format_percent = d3.format("%.00");
  +//
  +//                                    return format_percent(_.chain(data)
  +//                                            .map(function(d) { return d.count; })
  +//                                            .reduce(sum)
  +//                                            .value() / total_sequenced_patients);
                                   } else {
                                       return "<img width='20' height='20' id='pancan_mutations_histogram' src='images/ajax-loader.gif'/>";
                                   }
  
positive.code: <%@ page import="org.mskcc.cbio.portal.servlet.MutationsJSON" %>
  <%@ page import="org.mskcc.cbio.cgds.dao.DaoMutSig" %>
  
  <script type="text/javascript">
      var mutTableIndices = ["id", "case_ids", "gene", "aa", "chr", "start", "end", "ref", "_var",
              "validation", "type", "tumor_freq", "tumor_var_reads", "tumor_ref_reads",
  
negative.code: <div id="mutation_wait"><img src="images/ajax-loader.gif"/></div>
  <div id="mutation_id_filter_msg"><font color="red">The following table contains filtered mutations.</font>
  <button onclick="unfilterMutationsTableByIds(); return false;" style="font-size: 1em;">Show all mutations</button></div>
  <div  id="pancan_mutations_histogram_container"></div>
  <table cellpadding="0" cellspacing="0" border="0" id="mutation_wrapper_table" width="100%">
      <tr>
          <td>
  