1 hereditary colon cancer: lynch syndrome – past, present and the future henry t. lynch, md jane...

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HEREDITARY COLON CANCER: LYNCH SYNDROME – PAST, PRESENT AND THE

FUTURE

HENRY T. LYNCH, MDJANE F. LYNCH, BSN

Creighton UniversitySchool of MedicineOmaha, Nebraska

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Problem Areas

• Dx of Lynch syndrome (LS) frequently missed.

• Classification of LS may be ambiguous.

• More than CRC (numerous extracolonic cancers).

• Multiple molecular/phenotypic heterogeneous concerns.

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Family History

Must be comprehensive;

Cancer of all anatomic sites, verification whenever possible.

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Why Pursue Cancer of All Anatomic Sites?

Pertinent for any hereditary cancer syndromeMost identified by pattern of cancer expression, e.g.: • breast and ovary (HBOC syndrome); • CRC, endometrium, ovary, others (Lynch syndrome); • sarcomas, breast, brain, multiple others in SBLA (Li- Fraumeni syndrome); • medullary thyroid carcinoma and pheochromocytoma (MEN-2a and MEN-2b); • melanoma and pancreatic cancer with CDKN2A (p16) mutation (FAMMM syndrome); • diffuse gastric cancer and lobular breast cancer with CDH1 mutation (HDGC syndrome); ...and the list goes on.

Genetic Counseling

• Mandatory

• Centers of Cancer Genetic Expertise

• Physician Role, unfortunately, often insufficient

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Patient’s Modified Nuclear Pedigree

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Colorectal Cancer

Worldwide estimates for colorectal cancer during 2008*:Incidence – 1,233,711 Mortality – 608,644

Worldwide estimates for familial/hereditary CRC during 2008*:Lynch syndrome 3-5% of all CRC 37,011-61,686FAP <1% of all CRC <12,337Familial 20% of all CRC 246,742

*GLOBOCAN. The International Agency for Research on Cancer web site. URL: http://www.iarc.fr/

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Familial/Hereditary CRC in US

Annual CRC incidence in US: 142,570

Lynch syndrome 3-5% of all CRC 4,277 - 7,129

FAP <1% of all CRC <1,426

Familial 20% of all CRC 28,514

Jemal et al. CA Cancer J Clin 60:277-300,2010.

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Magnitude of the Problem

Question: Why are these figures of such significant public health impact?

Answer: Each hereditary cancer comes from a family that could benefit immensely from genetic counseling.

DNA testing, surveillance, and highly-targeted management are the key!

Problem: Significance of family frequently missed!

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THE BEGINNING!

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Archives of Internal MedicineVol. 12, July-Dec., 1913

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Archives of Internal Medicine Vol. 12, July-Dec., 1913

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Arch Intern Med 117:206-212, 1966.

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Arch Intern Med 117:206-212, 1966.

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Arch Intern Med 141:607-611, 1981

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Cancer Research 54:4590-4594, 1994.

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Am J Gastroenterology 89:1978-1980, 1994.

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How Aggressive?

Of 225 CRC patients with LS, 10.2 % had CRC within 5 yr of colonoscopy.

Other studies showed CRC within 3 yrs of colonoscopy.

Conclusion:

1) Accelerated carcinogenesis;2) Need shorter colonoscopy intervals.

Am J Gastrology 89:1978-1980, 1994.

24Cancer 83:259-266, 1998.

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Survival continuedResults:Compared with the unselected series, the

HNPCC cases had lower stage disease (P < 0.001), and fewer had distant metastases at diagnosis (P < 0.001 in an analysis stratified by T classification);

In stage-stratified survival analysis, the HNPCC cases had a significant overall survival advantage regardless of adjustment for their younger age;

Cancer 83:259-266, 1998.

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Survival continuedResults:A conservative estimate of the hazard ratio

(of HNPCC cases to the unselected series) was 0.67 (P < 0.0012).

The estimated death rate for the HNPCC cases, adjusted for stage and age differences, was at most two-thirds of the rate for the hospital series.

Cancer 83:259-266, 1998.

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Am. J. Hum. Genet. 72:1088-1100, 2003

28JAMA 291:718-724, 2004

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Genetic Heterogeneity in HNPCC

HNPCC is associated with germline HNPCC is associated with germline mutations in any one of at least five genesmutations in any one of at least five genes

Chr 2Chr 2Chr 3Chr 3

Chr 7Chr 7

MSH2MSH2

PMS1PMS1

MLH1MLH1PMS2PMS2

MSH6MSH6

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FUTURE!

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Should we test all colorectal cancer for

Lynch Syndrome?

YES! Test everybody.YES! Test everybody.

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Search for LS Among CRC Affecteds*

Evidence:

Among 500 CRC patients, 18 (3.6%) had LS.

Of these 18:

18 (100%) had MSI-H CRCs;

17 (94%) were correctly predicted by IHC;

only 8 (44%) were dx < 50 years;

only 13 (72%) met the revised Bethesda guidelines;

1/35 cases of CRC show LS.

*Hampel et al. J Clin Oncol 26:5783-5788, 2008.

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Molecular Genetic Screening for LS

Recommendation*:

All incident CRC and EC cases should be molecularly screened for LS.

MSI highly sensitive (89.3%).

IHC equally sensitive (91.2%), is inexpensive, is more readily available, and predicts the nonworking gene.

IHC is preferred method to screen for LS*.

*Hampel et al. J Clin Oncol 26:5783-5788, 2008.

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Increased risk for certain extracolonic malignancies

Endometrial Ovary Stomach Small bowel Pancreas Liver and biliary tree Muir-Torre cutaneous features Brain, (glioblastoma) – Turcot’s syndrome Possible Prostate cancer and others Breast cancer - controversial.

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Cardinal Features of Lynch Syndrome

• Differentiating pathology features of LS CRCs:

- more often poorly differentiated;

- excess of mucoid and signet-cell features;

- Crohn’s-like reaction;

- medullary features;

- significant excess of infiltrating lymphocytes

within the tumor.

• Increased survival from CRC.

• Sine qua non for diagnosis is identification of germline mutation in MMR gene (most commonly MLH1, MSH2, MSH6) segregating in the family.

A B

C D

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Cancer 77:1836-1843, 1996.

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Breast Cancer Research and Treatment 53:87-91, 1999.

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Breast Cancer in the Danish HNPCC Register*

20 ♀ mutation carriers dx with BC at mean age of 50 years (33-66).

Predominantly ductal carcinoma with extensive lymphocytic reactions in 8/14 evaluated tumors.

MMR protein immunostaining showed loss of expression of MLH1, MSH2, or MSH6 corresponding to the mutations found in 7/16 investigated cases.

*Jensen et al. Breast Cancer Res Treat 120:777- 782, 2010.

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Dis Colon Rectum 53:77-82, 2010.

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Times to subsequent CRC and subsequent abdominal surgery were significantly shorter in the control group (P < .006 and P < .04, respectively).

No significant difference was identified with respect to survival time between the cases and controls.

Conclusion: Even though no survival benefit was identified between the cases and controls the increased incidence of metachronous colorectal cancer and increased abdominal surgeries among controls warrant the recommendation of subtotal colectomy in patients with LS.

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N Engl J Med 354: 261-269, 2006

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BRAFV600E Mutations in MSI*

The BRAFV600E mutation occurs exclusively in sporadic forms of MSI CRC.

Combined analysis of MSI and BRAFV600E mutation is included in current protocols of LS since it is a reliable, fast, and low-cost strategy.

Helps identify sporadic cases and avoids time-consuming and expensive screening of MMR germline mutation analysis.

*Seruca et al. Expert Rev Gastroenterol Hepatol 3:5-9, 2009.

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Algorithm

1. IHC on all colorectal patients on tumor block;

2. If positive, BRAF (if positive, then sporadic);

3. Only do full MMR genetic tests on patient IHC +. BRAF neg.

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MORPHOLOGYSUSPICIOUS

FOR MSI-H

Run PCR testfor MSI status

Is thereMSI-H?

Run mutation analysisfor BRAF V600E

Is thereBRAF V600E

mutation?

SPORADIC CRCWITH MSI-H

NO EVIDENCE OFLYNCH

SYNDROME

Is there lossof stainingwith any ofthe Abs?

IHC for MLH1,MSH2, MSH6, PMS2

PUTATIVELYNCH

SYNDROME

MMR GENES MUTATIONANALYSIS

Is therea mutation in MMR

gene?

LYNCHSYNDROME

YES

YES

NO

NO

NO

YES

YES

NO

Gatalica Z, Torlakovic E. Fam Cancer 2008;7:15-26

FAMILIAL CRCTYPE “X”

MSI AnalysisMSI Analysis

A A functionalfunctional assay for assay for

the MMR proteinsthe MMR proteins

MSI AnalysisMSI Analysis

MSI High DataMSI High Data

New – Focus on Mononcleotides

MSI and Therapeutic Implications

Pharmacogenetics:

5-FU-based chemotherapy refractory in MSI CRCs;

possible advantage of irinotecan-based therapy;

the latter “not ready for prime time” but 5-FU approaching clinical acceptability.

Boland and Goel. Gastroenterology 138:2073-2087, 2010.

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MSI and Therapeutic Implications

Virtually all studies show either no benefit or adverse effects in response to 5-FU-based adjuvant chemotherapy (reviewed by Boland and Goel.*)

In vitro responses suggest that chemoresistance is seen for many chemotherapeutic agents.**

*Gastroenterology 138:2073-2087, 2010.

**Aebi et al. Cancer Res 56:3087-3090, 1996.

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MSI and Therapeutic Implications*

Currently, guidelines do not recommend using MSI status to determine whether or not to use chemotherapy.

This recommendation merits a second look, given the wealth of data showing the inadequacy of 5-FU for CRC with MSI.

Should be tested only in the context of a randomized clinical trial.

*Boland & Goel. Gastroenterology 138:2073-2087, 2010.

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Familial CRC Type “X”

Amsterdam Criteria positive but lacking MSI and MMR mutations will constitute ~ 40% of those AC-I without MMR mutations and therein referred to as familial CRC type X.*

1) CRC > left side

2) CRC and extra colonic CRC

3) Later age CRC onset

4) Molecular genetics (MSI and IHC or MMR

mutation) ABSENT!

*Lindor et al. JAMA 293:1979-1985, 2005.

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Epithelial Cell Adhesion Molecule (EPCAM) Gene and Its Lynch Syndrome Connection*

A portion of this ~40% lacking MMR mutations is caused by a mutation mechanism in the gene known as EPCAM.

*Kovacs et al. Hum Mutat 30:197-203, 2009.

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Polyadenylation Sequence

5’ EPCAM deletion Exons 8 and 9 and polyadenylation sequence

Ligtenberg MJ, Nature Genetics 2009.

Transcriptional read throughHypermethylation of the MSH2 promoter

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Why LS with Site-Specific CRC?

Deletion in EPCAM results in hypermethylation and incomplete silencing of MSH2.

EPCAM mutation carriers may have phenotypic features that differ from carriers of MSH2 mutations – namely, an almost exclusive expression of site-specific CRC, thereby lacking extracolonic cancers.

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c.859-1462_*1999del (4.9 kb, starting in intron 7 and including exons 8 & 9)

EPCAM MSH2

American and Dutch families have the same deletion in the EPCAM gene

Deletion

Lightenberg, Nature Genetics 2009.

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American and Dutch EPCAM mutations originate from a common ancestor

Deletion and Region inherited from

common ancestor

Family R and the Dutch families share a 6.1 MB region surrounding the same EPCAM deletion indicating a common ancestor. Based on the size of the

shared region it is estimated the deletion occurred 10 generations ago.

Dutch Families

Chromosome 2

Family R

Chromosome 2

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History of Family R*

Ascertained by us in 1970 and followed continuously.

700 blood line relatives

327 individuals age ≥ 18, ≥ 25% pedigree risk

Phenotype strikingly similar to LS but integral extracolonic cancers absent (site-specific CRCs)

*Lynch et al. Cancer 56:934-938, 1985.

Lynch et al. Cancer 56:939-951, 1985.

63First patient identified with EPCAM mutation

CRC affecteds EPCAM results

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Family Information Service (FIS)

Cost-effective and highly efficient way of educating and counseling all available family members from a geographic catchment area during a single setting.

Makes best use of physician’s time and effort, has group therapy potential and patients welcome it.

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Targeted CRC Screening

Screening is melded to LS’s natural history:

Proximal location colonoscopy

Early age of onset beginning at age 25

Accelerated carcinogenesis every 1-2 yrs < age 40, then annually

Pattern of extra-colonic cancers targeted screening

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MSI/IHC in CRC*Conclusion:

CRCs with MSI may show distinctive clinical, pathologic features:

a) predominance of CRC in proximal colon;

b) lymphocyte infiltration within tumor;

c) poorly differentiated mucinous or signet cell appearance;

d) better prognosis;

e) differing response to chemotherapeutics;

f) molecular screening all CRC cases.

*Boland and Goel. Gastroenterology 138:2073-2087, 2010.

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*Jensen et al. Breast Cancer Res Treat 120:777-782, 2010.

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Breast Cancer in the Danish HNPCC Register*

Defective MMR in a substantial proportion of the BCs studied links it to HNPCC.

While the low number does not motivate surveillance, the observation supports a role for defective MMR in BC progression in LS.

*Jensen et al. Breast Cancer Res Treat 120:777- 782, 2010.

MSI and Therapeutic Implications*

Where did this knowledge originate?

Through DNA MMR genes first identified in bacteria through exposure to cytotoxic mutagens (alkylating agents) and selecting for strains resistant to DNA damage.

*Carethers et al. J Clin Invest 98:199-206, 1996.

Ribic et al. N Engl J Med 349:247-257, 2003.

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MSI and Therapeutic Implications*

Resulting bacteria were hypermutable and resistant to DNA alkylation.

Resistant to cytotoxic agents that acted by damaging DNA.

Raised possibility that DNA MMR deficient cells might be relatively resistant to some types of cytotoxic chemotherapy.

*Carethers et al. J Clin Invest 98:199-206, 1996.

Ribic et al. N Engl J Med 349:247-257, 2003.

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Cardinal Features of Lynch Syndrome

• AD – MMR mutations• Proximal• Earlier age of onset• Accelerated carcinogenesis • Extra colonic cancers• Pathology – distinctive?• ↑ survival