BRST5:Tall cell carcinoma with reversed polarity

Primary Author(s)*

H. Evin Gulbahce, MD, MSCI, University of Utah, UT

WHO Classification of Disease

(Instructions: This table’s content from the WHO book will be autocompleted.)

Structure	Disease
Book
Category
Family
Type
Subtype(s)

WHO Essential and Desirable Genetic Diagnostic Criteria

(Instructions: The table will have the diagnostic criteria from the WHO book autocompleted; remove any non-genetics related criteria. If applicable, add text about other classification systems that define this entity and specify how the genetics-related criteria differ.)

WHO Essential Criteria (Genetics)*
WHO Desirable Criteria (Genetics)*
Other Classification

*Note: These are only the genetic/genomic criteria. Additional diagnostic criteria can be found in the WHO Classification of Tumours.

Related Terminology

(Instructions: The table will have the related terminology from the WHO autocompleted.)

Acceptable
Not Recommended

Gene Rearrangements

Driver Gene	Fusion(s) and Common Partner Genes	Molecular Pathogenesis	Typical Chromosomal Alteration(s)	Prevalence -Common >20%, Recurrent 5-20% or Rare <5% (Disease)	Diagnostic, Prognostic, and Therapeutic Significance - D, P, T	Established Clinical Significance Per Guidelines - Yes or No (Source)	Clinical Relevance Details/Other Notes

Individual Region Genomic Gain/Loss/LOH

Chr #	Gain, Loss, Amp, LOH	Minimal Region Cytoband and/or Genomic Coordinates [Genome Build; Size]	Relevant Gene(s)	Diagnostic, Prognostic, and Therapeutic Significance - D, P, T	Established Clinical Significance Per Guidelines - Yes or No (Source)	Clinical Relevance Details/Other Notes

Characteristic Chromosomal or Other Global Mutational Patterns

Chromosomal Pattern	Molecular Pathogenesis	Prevalence - Common >20%, Recurrent 5-20% or Rare <5% (Disease)	Diagnostic, Prognostic, and Therapeutic Significance - D, P, T	Established Clinical Significance Per Guidelines - Yes or No (Source)	Clinical Relevance Details/Other Notes

Gene Mutations (SNV/INDEL)

Gene	Genetic Alteration	Tumor Suppressor Gene, Oncogene, Other	Prevalence - Common >20%, Recurrent 5-20% or Rare <5% (Disease)	Diagnostic, Prognostic, and Therapeutic Significance - D, P, T	Established Clinical Significance Per Guidelines - Yes or No (Source)	Clinical Relevance Details/Other Notes
IDH2	codon 172 mutations	Oncogene	Common	D	Yes (WHO)	Majority are R172S, R172T; others include R172G, R172W, R172I
PIK3CA		Oncogene	Common	T	Yes (NCCN)	Co-mutated with IDH2; hotspots include H1047R, E542K, E545K

Note: A more extensive list of mutations can be found in cBioportal, COSMIC, and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.

Epigenomic Alterations

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Genes and Main Pathways Involved

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Gene; Genetic Alteration	Pathway	Pathophysiologic Outcome
IDH2	Carbon metabolism; carboxylic acid (Krebs) cycle	Increased conversion of α-ketoglutarate (α-KG) to the oncometabolite R-2-hydroxylglutarate (R-2-HG). Increased levels of 2-HG result in hypermethylation of epigenetic targets and a subsequent block in cellular differentiation. Due to widespread hypermethylation, there is increased H3K27me3 nuclear immunoreactivity in tumors harboring IDH2 R172 mutations.
PIK3CA	PI3K/AKT/mTOR pathway	Three most common PIK3CA mutations are H1047R, E542K, and E545K; PIK3CA mutations induce hyperactivation of the alpha isoform of the catalytic subunit (p110α) of class IA PI3K kinase. Mutations are often co-occurring with other drivers in ER-positive breast cancers and are associated with endocrine resistance. PIK3CA mutations are targetable with the PI3K inhibitor alpelisib in ER positive breast cancers; however, tall cell carcinoma with reverse polarity is usually ER negative.

Genetic Diagnostic Testing Methods

Next generation sequencing (NGS); immunohistochemistry with monoclonal antibodies against IDH2 mutant codon R172S (monoclonal antibody clone 11C8B1 is reactive against R172S or R172T); pyrosequencing; Sanger sequencing; PCR with allele detection (examples include PCR with melting curve analysis, or PCR with use of allele-specific probes); allele-specific PCR; single base extension.  

Familial Forms

None

Links

https://www.pathologyoutlines.com/topic/breastmalignantspcrp.html

Notes

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Prior Author(s):  

References

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