How to convert XML NER data from the CRAFT corpus to spaCy's JSON format?

Question

How to build a named entity recognition(NER) model using spaCy for biomedical NER on CRAFT corpus ?

It is difficult for me to pre-process the xml files given in that corpus to any format used by spacy , any little help would be highly appreciated. I first converted the xml files to json format but that was not accepted by spacy . What format of training data does spacy expect? I even tried to build my own NER model but was not able to pre-process the xml files as given in this article .

Here is an example of training an NER model using spacy, including the expected format of training data (from spacy's docs ):

import random

import spacy


TRAIN_DATA = [
        ("Uber blew through $1 million a week", {"entities": [(0, 4, "ORG")]}),
        ("Google rebrands its business apps", {"entities": [(0, 6, "ORG")]})]

nlp = spacy.blank("en")
optimizer = nlp.begin_training()
for i in range(20):
    random.shuffle(TRAIN_DATA)
    for text, annotations in TRAIN_DATA:
        nlp.update([text], [annotations], sgd=optimizer)
nlp.to_disk("/model")

The XML file I am using is available online here . An example record looks like:

<passage>
<infon key="section_type">ABSTRACT</infon>
<infon key="type">abstract</infon>
<offset>141</offset>
<text>
Breast cancer is the most frequent tumor in women, and in nearly two-thirds of cases, the tumors express estrogen receptor alpha (ERalpha, encoded by ESR1). Here, we performed whole-exome sequencing of 16 breast cancer tissues classified according to ESR1 expression and 12 samples of whole blood, and detected 310 somatic mutations in cancer tissues with high levels of ESR1 expression. Of the somatic mutations validated by a different deep sequencer, a novel nonsense somatic mutation, c.2830 C>T; p.Gln944*, in transcriptional regulator switch-independent 3 family member A (SIN3A) was detected in breast cancer of a patient. Part of the mutant protein localized in the cytoplasm in contrast to the nuclear localization of ERalpha, and induced a significant increase in ESR1 mRNA. The SIN3A mutation obviously enhanced MCF7 cell proliferation. In tissue sections from the breast cancer patient with the SIN3A c.2830 C>T mutation, cytoplasmic SIN3A localization was detected within the tumor regions where nuclear enlargement was observed. The reduction in SIN3A mRNA correlates with the recurrence of ER-positive breast cancers on Kaplan-Meier plots. These observations reveal that the SIN3A mutation has lost its transcriptional repression function due to its cytoplasmic localization, and that this repression may contribute to the progression of breast cancer.
</text>
<annotation id="38">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="246" length="23"/>
<text>estrogen receptor alpha</text>
</annotation>
<annotation id="39">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="271" length="7"/>
<text>ERalpha</text>
</annotation>
<annotation id="40">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="291" length="4"/>
<text>ESR1</text>
</annotation>
<annotation id="41">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="392" length="4"/>
<text>ESR1</text>
</annotation>
<annotation id="42">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="512" length="4"/>
<text>ESR1</text>
</annotation>
<annotation id="43">
<infon key="identifier">25942</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">32124</infon>
<location offset="720" length="5"/>
<text>SIN3A</text>
</annotation>
<annotation id="44">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="868" length="7"/>
<text>ERalpha</text>
</annotation>
<annotation id="45">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="915" length="4"/>
<text>ESR1</text>
</annotation>
<annotation id="46">
<infon key="identifier">25942</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">32124</infon>
<location offset="930" length="5"/>
<text>SIN3A</text>
</annotation>
<annotation id="47">
<infon key="identifier">25942</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">32124</infon>
<location offset="1048" length="5"/>
<text>SIN3A</text>
</annotation>
<annotation id="48">
<infon key="identifier">25942</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">32124</infon>
<location offset="1087" length="5"/>
<text>SIN3A</text>
</annotation>
<annotation id="49">
<infon key="identifier">25942</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">32124</infon>
<location offset="1201" length="5"/>
<text>SIN3A</text>
</annotation>
<annotation id="50">
<infon key="identifier">25942</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">32124</infon>
<location offset="1331" length="5"/>
<text>SIN3A</text>
</annotation>
<annotation id="51">
<infon key="identifier">9606</infon>
<infon key="type">Species</infon>
<location offset="185" length="5"/>
<text>women</text>
</annotation>
<annotation id="52">
<infon key="identifier">9606</infon>
<infon key="type">Species</infon>
<location offset="762" length="7"/>
<text>patient</text>
</annotation>
<annotation id="53">
<infon key="identifier">9606</infon>
<infon key="type">Species</infon>
<location offset="1031" length="7"/>
<text>patient</text>
</annotation>
<annotation id="54">
<infon key="identifier">29278</infon>
<infon key="type">Species</infon>
<location offset="397" length="10"/>
<text>expression</text>
</annotation>
<annotation id="55">
<infon key="identifier">29278</infon>
<infon key="type">Species</infon>
<location offset="517" length="10"/>
<text>expression</text>
</annotation>
<annotation id="56">
<infon key="identifier">c.2830C>T</infon>
<infon key="type">DNAMutation</infon>
<location offset="1054" length="10"/>
<text>c.2830 C>T</text>
</annotation>
<annotation id="57">
<infon key="identifier">CVCL:0031</infon>
<infon key="type">CellLine</infon>
<location offset="964" length="4"/>
<text>MCF7</text>
</annotation>
<annotation id="58">
<infon key="identifier">MESH:D001943</infon>
<infon key="type">Disease</infon>
<location offset="1494" length="13"/>
<text>breast cancer</text>
</annotation>
<annotation id="59">
<infon key="identifier">MESH:D001943</infon>
<infon key="type">Disease</infon>
<location offset="346" length="13"/>
<text>breast cancer</text>
</annotation>
<annotation id="60">
<infon key="identifier">MESH:D001943</infon>
<infon key="type">Disease</infon>
<location offset="743" length="13"/>
<text>breast cancer</text>
</annotation>
<annotation id="61">
<infon key="identifier">MESH:D001943</infon>
<infon key="type">Disease</infon>
<location offset="1017" length="13"/>
<text>breast cancer</text>
</annotation>
<annotation id="62">
<infon key="identifier">MESH:D009369</infon>
<infon key="type">Disease</infon>
<location offset="477" length="6"/>
<text>cancer</text>
</annotation>
<annotation id="63">
<infon key="identifier">p.Q944*</infon>
<infon key="type">ProteinMutation</infon>
<location offset="642" length="9"/>
<text>p.Gln944*</text>
</annotation>
<annotation id="64">
<infon key="identifier">MESH:D009369</infon>
<infon key="type">Disease</infon>
<location offset="1130" length="5"/>
<text>tumor</text>
</annotation>
<annotation id="65">
<infon key="identifier">MESH:D009369</infon>
<infon key="type">Disease</infon>
<location offset="176" length="5"/>
<text>tumor</text>
</annotation>
<annotation id="66">
<infon key="identifier">c.2830C>T</infon>
<infon key="type">DNAMutation</infon>
<location offset="630" length="10"/>
<text>c.2830 C>T</text>
</annotation>
<annotation id="67">
<infon key="identifier">MESH:D001943</infon>
<infon key="type">Disease</infon>
<location offset="1258" length="14"/>
<text>breast cancers</text>
</annotation>
<annotation id="68">
<infon key="identifier">MESH:D009369</infon>
<infon key="type">Disease</infon>
<location offset="231" length="6"/>
<text>tumors</text>
</annotation>
<annotation id="69">
<infon key="identifier">MESH:D001943</infon>
<infon key="type">Disease</infon>
<location offset="141" length="13"/>
<text>Breast cancer</text>
</annotation>
</passage>

Answer 1

Here is some code to get you going. It is not a complete solution, but the problem you posed is very hard, and you didn't have any starter code.

It does not track the identifier or NCBI Homologene properties, but I think those can be stored in a dictionary separately.

import xml.etree.cElementTree as ET

import spacy

nlp = spacy.load('en_core_web_sm')

# this is one child of the XML doc
# https://www.ncbi.nlm.nih.gov/research/pubtator-api/publications/export/biocxml?pmcids=PMC6207735
passage_string = """
<passage>
<infon key="section_type">ABSTRACT</infon>
<infon key="type">abstract</infon>
<offset>141</offset>
<text>
Breast cancer is the most frequent tumor in women, and in nearly two-thirds of cases, the tumors express estrogen receptor alpha (ERalpha, encoded by ESR1). Here, we performed whole-exome sequencing of 16 breast cancer tissues classified according to ESR1 expression and 12 samples of whole blood, and detected 310 somatic mutations in cancer tissues with high levels of ESR1 expression. Of the somatic mutations validated by a different deep sequencer, a novel nonsense somatic mutation, c.2830 C>T; p.Gln944*, in transcriptional regulator switch-independent 3 family member A (SIN3A) was detected in breast cancer of a patient. Part of the mutant protein localized in the cytoplasm in contrast to the nuclear localization of ERalpha, and induced a significant increase in ESR1 mRNA. The SIN3A mutation obviously enhanced MCF7 cell proliferation. In tissue sections from the breast cancer patient with the SIN3A c.2830 C>T mutation, cytoplasmic SIN3A localization was detected within the tumor regions where nuclear enlargement was observed. The reduction in SIN3A mRNA correlates with the recurrence of ER-positive breast cancers on Kaplan-Meier plots. These observations reveal that the SIN3A mutation has lost its transcriptional repression function due to its cytoplasmic localization, and that this repression may contribute to the progression of breast cancer.
</text>
<annotation id="38">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="246" length="23"/>
<text>estrogen receptor alpha</text>
</annotation>
<annotation id="39">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="271" length="7"/>
<text>ERalpha</text>
</annotation>
<annotation id="40">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="291" length="4"/>
<text>ESR1</text>
</annotation>
<annotation id="41">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="392" length="4"/>
<text>ESR1</text>
</annotation>
<annotation id="42">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="512" length="4"/>
<text>ESR1</text>
</annotation>
<annotation id="43">
<infon key="identifier">25942</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">32124</infon>
<location offset="720" length="5"/>
<text>SIN3A</text>
</annotation>
<annotation id="44">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="868" length="7"/>
<text>ERalpha</text>
</annotation>
<annotation id="45">
<infon key="identifier">2099</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">47906</infon>
<location offset="915" length="4"/>
<text>ESR1</text>
</annotation>
<annotation id="46">
<infon key="identifier">25942</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">32124</infon>
<location offset="930" length="5"/>
<text>SIN3A</text>
</annotation>
<annotation id="47">
<infon key="identifier">25942</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">32124</infon>
<location offset="1048" length="5"/>
<text>SIN3A</text>
</annotation>
<annotation id="48">
<infon key="identifier">25942</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">32124</infon>
<location offset="1087" length="5"/>
<text>SIN3A</text>
</annotation>
<annotation id="49">
<infon key="identifier">25942</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">32124</infon>
<location offset="1201" length="5"/>
<text>SIN3A</text>
</annotation>
<annotation id="50">
<infon key="identifier">25942</infon>
<infon key="type">Gene</infon>
<infon key="NCBI Homologene">32124</infon>
<location offset="1331" length="5"/>
<text>SIN3A</text>
</annotation>
<annotation id="51">
<infon key="identifier">9606</infon>
<infon key="type">Species</infon>
<location offset="185" length="5"/>
<text>women</text>
</annotation>
<annotation id="52">
<infon key="identifier">9606</infon>
<infon key="type">Species</infon>
<location offset="762" length="7"/>
<text>patient</text>
</annotation>
<annotation id="53">
<infon key="identifier">9606</infon>
<infon key="type">Species</infon>
<location offset="1031" length="7"/>
<text>patient</text>
</annotation>
<annotation id="54">
<infon key="identifier">29278</infon>
<infon key="type">Species</infon>
<location offset="397" length="10"/>
<text>expression</text>
</annotation>
<annotation id="55">
<infon key="identifier">29278</infon>
<infon key="type">Species</infon>
<location offset="517" length="10"/>
<text>expression</text>
</annotation>
<annotation id="56">
<infon key="identifier">c.2830C>T</infon>
<infon key="type">DNAMutation</infon>
<location offset="1054" length="10"/>
<text>c.2830 C>T</text>
</annotation>
<annotation id="57">
<infon key="identifier">CVCL:0031</infon>
<infon key="type">CellLine</infon>
<location offset="964" length="4"/>
<text>MCF7</text>
</annotation>
<annotation id="58">
<infon key="identifier">MESH:D001943</infon>
<infon key="type">Disease</infon>
<location offset="1494" length="13"/>
<text>breast cancer</text>
</annotation>
<annotation id="59">
<infon key="identifier">MESH:D001943</infon>
<infon key="type">Disease</infon>
<location offset="346" length="13"/>
<text>breast cancer</text>
</annotation>
<annotation id="60">
<infon key="identifier">MESH:D001943</infon>
<infon key="type">Disease</infon>
<location offset="743" length="13"/>
<text>breast cancer</text>
</annotation>
<annotation id="61">
<infon key="identifier">MESH:D001943</infon>
<infon key="type">Disease</infon>
<location offset="1017" length="13"/>
<text>breast cancer</text>
</annotation>
<annotation id="62">
<infon key="identifier">MESH:D009369</infon>
<infon key="type">Disease</infon>
<location offset="477" length="6"/>
<text>cancer</text>
</annotation>
<annotation id="63">
<infon key="identifier">p.Q944*</infon>
<infon key="type">ProteinMutation</infon>
<location offset="642" length="9"/>
<text>p.Gln944*</text>
</annotation>
<annotation id="64">
<infon key="identifier">MESH:D009369</infon>
<infon key="type">Disease</infon>
<location offset="1130" length="5"/>
<text>tumor</text>
</annotation>
<annotation id="65">
<infon key="identifier">MESH:D009369</infon>
<infon key="type">Disease</infon>
<location offset="176" length="5"/>
<text>tumor</text>
</annotation>
<annotation id="66">
<infon key="identifier">c.2830C>T</infon>
<infon key="type">DNAMutation</infon>
<location offset="630" length="10"/>
<text>c.2830 C>T</text>
</annotation>
<annotation id="67">
<infon key="identifier">MESH:D001943</infon>
<infon key="type">Disease</infon>
<location offset="1258" length="14"/>
<text>breast cancers</text>
</annotation>
<annotation id="68">
<infon key="identifier">MESH:D009369</infon>
<infon key="type">Disease</infon>
<location offset="231" length="6"/>
<text>tumors</text>
</annotation>
<annotation id="69">
<infon key="identifier">MESH:D001943</infon>
<infon key="type">Disease</infon>
<location offset="141" length="13"/>
<text>Breast cancer</text>
</annotation>
</passage>"""

# turn into an object
passage = ET.fromstring(passage_string)

# these 3 definitions are per-passage
passage_annotations = passage.findall('./annotation')
passage_offset = int(passage.find('offset').text)
passage_text = passage.find('text').text

def get_entity_offset(offset_dict, passage_offset):
    """
    XML given offset_dict gives offset relative to the start of the document
    So subtract the passage offset (where passage starts relative to document beginning)
    """
    start = int(offset_dict['offset']) - passage_offset
    end = int(offset_dict['offset']) + (int(offset_dict['length']) + 1) - passage_offset
    return start, end

# collect entities as a list of tuples of the form
# (start, end, entitiy_type)
passage_entities = []
for ann in passage_annotations:
    entity_type = ann.find('./infon[@key="type"]').text
    od = ann.find('./location').attrib
    start, end = get_entity_offset(od, passage_offset)
    passage_entities.append((start, end, entity_type))

# this is one entry in the spacy NER format
# you would want many entries
spacyd_passage = (passage_text, {"entities": passage_entities})

# prove this worked
for ent in passage_entities:
    print(ent, passage_text[ent[0]:ent[1]])

# prints:
# (105, 129, 'Gene')  estrogen receptor alpha
# (130, 138, 'Gene') (ERalpha
# (150, 155, 'Gene')  ESR1
# (251, 256, 'Gene')  ESR1
# (371, 376, 'Gene')  ESR1
# (579, 585, 'Gene') (SIN3A
# (727, 735, 'Gene')  ERalpha
# (774, 779, 'Gene')  ESR1
# (789, 795, 'Gene')  SIN3A
# (907, 913, 'Gene')  SIN3A
# (946, 952, 'Gene')  SIN3A
# (1060, 1066, 'Gene')  SIN3A
# (1190, 1196, 'Gene')  SIN3A
# (44, 50, 'Species')  women
# (621, 629, 'Species')  patient
# (890, 898, 'Species')  patient
# (256, 267, 'Species')  expression
# (376, 387, 'Species')  expression
# (913, 924, 'DNAMutation')  c.2830 C>T
# (823, 828, 'CellLine')  MCF7
# (1353, 1367, 'Disease')  breast cancer
# (205, 219, 'Disease')  breast cancer
# (602, 616, 'Disease')  breast cancer
# (876, 890, 'Disease')  breast cancer
# (336, 343, 'Disease')  cancer
# (501, 511, 'ProteinMutation')  p.Gln944*
# (989, 995, 'Disease')  tumor
# (35, 41, 'Disease')  tumor
# (489, 500, 'DNAMutation')  c.2830 C>T
# (1117, 1132, 'Disease')  breast cancers
# (90, 97, 'Disease')  tumors
# (0, 14, 'Disease')  Breast cancer

So, the first thing I notice is that some of the given offsets are slightly off, catching ( . You could look for if passage_text[ent[0]] == "(" and shift the start of the entity by 1 to clean that, or clean it manually.

Also, this code uses one child node, a passage of the linked doc. You will want to download that doc locally, and instead of passage = ET.fromstring(passage_string) , you will create tree = ET.parse('path_to_file') :

Something like

import xml.etree.cElementTree as ET

tree = ET.parse('path_to_file')
root = tree.getroot()
passages = root.findall('./passages')

spacy_data = []

for passage in passages:
    passage_annotations = passage.findall('./annotation')
    passage_offset = int(passage.find('offset').text)
    passage_text = passage.find('text').text

    passage_entities = []
    for ann in passage_annotations:
        entity_type = ann.find('./infon[@key="type"]').text
        od = ann.find('./location').attrib
        start, end = get_entity_offset(od, passage_offset)
        passage_entities.append((start, end, entity_type))

        spacyd_passage = (passage_text, {"entities": passage_entities})
        spacy_data.append(spacyd_package)

This can still be improved upon. You'll want to split those passage.text passages using

import spacy

nlp = spacy.load('en_core_web_sm')

doc = nlp(passage_text)
sents = list(doc.sents)

But the tricky part is you need to do arithmetic to keep the offset indices correct. And you will also want to look at the start and end of each entity to make sure it stays within one sentence - it conceivably could be split by a sentence boundary, though probably not.