Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2010 Feb;120(2):636-44.
doi: 10.1172/JCI40724. Epub 2010 Jan 25.

Cellular and genetic diversity in the progression of in situ human breast carcinomas to an invasive phenotype

So Yeon Park  1 , Mithat Gönen, Hee Jung Kim, Franziska Michor, Kornelia Polyak
Affiliations

Cellular and genetic diversity in the progression of in situ human breast carcinomas to an invasive phenotype

So Yeon Park et al. J Clin Invest. 2010 Feb.

Abstract

Intratumor genetic heterogeneity is a key mechanism underlying tumor progression and therapeutic resistance. The prevailing model for explaining intratumor diversity, the clonal evolution model, has recently been challenged by proponents of the cancer stem cell hypothesis. To investigate this issue, we performed combined analyses of markers associated with cellular differentiation states and genotypic alterations in human breast carcinomas and evaluated diversity with ecological and evolutionary methods. Our analyses showed a high degree of genetic heterogeneity both within and between distinct tumor cell populations that were defined based on markers of cellular phenotypes including stem cell-like characteristics. In several tumors, stem cell-like and more-differentiated cancer cell populations were genetically distinct, leading us to question the validity of a simple differentiation hierarchy-based cancer stem cell model. The degree of diversity correlated with clinically relevant breast tumor subtypes and in some tumors was markedly different between the in situ and invasive cell populations. We also found that diversity measures were associated with clinical variables. Our findings highlight the importance of genetic diversity in intratumor heterogeneity and the value of analyzing tumors as distinct populations of cancer cells to more effectively plan treatments.

PubMed Disclaimer

Figures

Figure 1
Figure 1. Cellular and genetic diversity in breast cancer defined by iFISH analysis.
A representative example (tumor 2) of HER2+ invasive ductal breast carcinoma with adjacent DCIS displaying a high degree of diversity for the expression of HER2, CD44, and CD24 and for copy number gain of ERBB2 and 8q24 based on immunohistochemical staining and iFISH, respectively. CD24 showed membrano-cytoplasmic expression in invasive tumor cells but apical membranous expression in DCIS. In iFISH, blue corresponds to CD24 or CD44 immunofluorescence; ERBB2 and 8q24-specific probes are red; and centromeric probes (chromosomes 17 and 8 for ERBB2 and 8q24, respectively) are green. Faint green and yellow are background autofluorescence. Scale bars: 10 μm; original magnification, ×400 (immunohistochemistry) and ×600 (iFISH).
Figure 2
Figure 2. Clonal evolution during in situ to invasive breast carcinoma progression detected by iFISH.
iFISH analyses using 11q13/CCDN1 (red) and chromosome 11 centromeric probe (green) in a luminal A subtype breast cancer (tumor 10). In the invasive areas, both CD44+ and CD24+ tumor cells (blue) display high-level amplification, whereas in adjacent DCIS, this is restricted to a subset of CD24+CD44+ tumor cells (dotted line), with the majority of the tumor demonstrating normal copy number for this locus. iFISH analysis of adjacent sections using 8q24 (red) and chromosome 8 centromeric probe (green) demonstrates normal (2n) copy numbers for 8q24 in both DCIS and invasive areas. Faint green and yellow are background autofluorescence. Yellow spots and lines are autofluorescent collagen fibers. Scale bars: 10 μm; original magnification, ×600.
Figure 3
Figure 3. Diversity for 8q24 copy number gain in breast tumors.
In basal-like tumors, CD24+ corresponds to CD44– cells, because no CD24 expression is seen in these cases. (A) Box plots depicting the distribution of 8q24 copy number gain defined as the ratio of signal observed for the 8q24-specific and centromeric probes in 100 individual cells in each of the 4 indicated tumor cell subpopulations. The filled circle represents the mean; boxes show the 25th to 75th percentiles; the horizontal lines inside the boxes represent the median; whiskers extend to the 10th and 90th percentiles; and outlying black circles are individual data points outside the 10th and 90th percentiles. Differences are seen between cell populations and also progression stages both for median copy number gain and for range of distribution. (B) Histograms and kernel density estimates depicting the distribution of cells with the indicated copy number ratio. Differences are seen between DCIS and invasive areas of the same tumor (e.g., tumor 4 [T4]) and also between CD24+ and CD44+ cells within the same compartment (e.g., T13A).
Figure 4
Figure 4. Diversity for 8q24 copy number gain in breast tumors defined by Shannon index and Whittaker plots.
In basal-like tumors, CD24+ corresponds to CD44– cells, because no CD24 expression is seen in these cases. (A) The Shannon index, H, indicating diversity within tumor cell subpopulations and tumors. For each tumor, 100 different cells for each of the 4 different types (IDC CD24+, IDC CD44+, DCIS CD24+, and DCIS CD44+) were analyzed, and their Shannon indices are depicted in dark blue, dark red, light blue, and light red, respectively. Higher score indicates higher diversity. Basal-like tumors are all uniformly highly diverse for 8q24, whereas a subset of HER2+ and luminal A tumors show a lower degree of diversity. (B) Whittaker plots (rank-abundance plots) depicting the abundance of unique cancer cells.
Figure 5
Figure 5. Diversity for different chromosomal probes in breast tumor subtypes and their association with histopathologic features.
(A) Hierarchical clustering of tumor samples based on the Shannon index for the 8q24 probe. Heatmap and dendrograms displaying relatedness of cell types and tumor samples based on their Shannon indices. Red and yellow correspond to high and low diversity, respectively, whereas white represents median levels. Tumor names are colored according to subtype: red, basal-like; pink, HER2+; and blue, luminal A. The color key indicates the correlation between diversity and colors. (B) Differences in diversity for different chromosomal regions in the same tumor. Histograms of copy number ratios in 4 distinct cell types for 3 different chromosomal probes are depicted in 2 individual tumors.
See this image and copyright information in PMC

Comment in

  • The role of genetic diversity in cancer.
    Merlo LM, Maley CC. Merlo LM, et al. J Clin Invest. 2010 Feb;120(2):401-3. doi: 10.1172/JCI42088. Epub 2010 Jan 25. J Clin Invest. 2010. PMID: 20101092 Free PMC article.

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Heppner GH, Loveless SE, Miller FR, Mahoney KH, Fulton AM. Mammary tumor heterogeneity. Symp Fundam Cancer Res. 1983;36:209–221. - PubMed
    1. Heppner GH, Miller BE. Tumor heterogeneity: biological implications and therapeutic consequences. Cancer Metastasis Rev. 1983;2(1):5–23. - PubMed
    1. Merlo LM, Pepper JW, Reid BJ, Maley CC. Cancer as an evolutionary and ecological process. Nat Rev Cancer. 2006;6(12):924–935. doi: 10.1038/nrc2013. - DOI - PubMed
    1. Maley CC, et al. Genetic clonal diversity predicts progression to esophageal adenocarcinoma. Nat Genet. 2006;38(4):468–473. doi: 10.1038/ng1768. - DOI - PubMed
    1. Gonzalez-Garcia I, Sole RV, Costa J. Metapopulation dynamics and spatial heterogeneity in cancer. Proc Natl Acad Sci U S A. 2002;99(20):13085–13089. doi: 10.1073/pnas.202139299. - DOI - PMC - PubMed

Publication types