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NAACCR Data Dictionary
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Version 25
Data Item #1189: Chromosome 16q: Loss of Heterozygosity

* indicates required field

Length: 1
Source of Standard: NAACCR/SEER
Section Name: Stage/Prognostic Factors
Year Implemented: 2025
Version Implemented: 25
Record Types: C, A, I, M

XML NAACCR ID: chromosome16qLossHeterozygosity

Parent XML Element: Tumor

Required Status:

NPCR Collect: . - No recommendations
CoC Collect: . - No recommendations
SEER Collect: RS* - Required, site specific; when available
CCCR Collect: . - No recommendations

Description:

Chromosome 16q: Loss of Heterozygosity (LOH) refers to the loss of genetic material normally found on the short arm of one of the patient's two copies of chromosome 16. Occurs in approximately 5% of favorable (non-anaplastic) histology Wilm’s tumor (FHWT) cells and has been shown to be associated with inferior relapse-free survival (RFS) and overall survival (OS) in patients with FH Wilm’s tumor. This testing is commonly done in conjunction with Chromosome 1p: Loss of Heterozygosity (NAACCR ID: 3801) and Chromosome 1q: Gain of heterozygosity (GOH). (NAACCR ID: 1190: Chromosome 1q Status).

This is a special molecular diagnostic test performed on tumor tissue to identify loss of genetic material found on the long arm of one of the patient’s two copies of chromosome 16. A normal cell will contain two complete copies of each chromosome, one from each parent, and this normal state is termed heterozygous. Loss of heterozygosity (LOH) is an abnormal state reflecting loss of the whole arm of chromosome 16q following a chromosomal translocation event.

Rationale:

This is part of the National Childhood Cancer Registry (NCCR) project to collect more specific information on pediatric patients. Registries part of the NCCR will start collection on specific pediatric data items with 2024+ diagnoses.

General Notes:

Source documents: molecular pathology report (may be addendum to original pathology report).

Item Data Type:

numeric

Allowable Values

0, 1, 7, 8,9

Codes:

0

Chromosome 16q deletion/LOH not identified/not present/negative

1

Chromosome 16q deletion/LOH present/positive

7

Test ordered, results not in chart

8

Not applicable:  Information not collected for this case
(If this item is required by your standard setter, use of code 8 will result in an edit error.)

9

Not documented in medical record

Cannot be determined by pathologist

Chromosome 16q: LOH not assessed or unknown if assessed

Code Notes:

Note 1: Effective years

  • This SSDI is effective for diagnosis years 2024+
  • For cases diagnosed 2018-2023, this SSDI must be blank

Note 2: Physician statement

  • Physician statement of Chromosome 16q deletion/LOH can be used to code this data item when no other information is available.